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❓:A technology analyst is evaluating the long-term business strategies of a tech startup founded by an innovative entrepreneur. The founder has developed a unique algorithm that predicts market trends based on a combination of historical data and social media sentiment analysis. The algorithm’s accuracy improves over time as it processes more data, modeled by the function ( A(t) = frac{100}{1 + e^{-0.1(t - 50)}} ), where ( A(t) ) represents the accuracy percentage of the algorithm after ( t ) weeks.1. Calculate the time ( t ) in weeks when the algorithm reaches 90% accuracy. 2. The founder plans to invest in infrastructure to double the data processing speed, which will effectively halve the time ( t ) needed to reach any given accuracy level. If the investment costs 500,000 and is expected to increase profits by 10,000 per week once the algorithm reaches 90% accuracy, determine the minimum number of weeks after reaching 90% accuracy when the investment will break even. Assume that profits continue to grow at the same rate indefinitely.
🧠:<think>Alright, so I have this problem about a tech startup with a unique algorithm for predicting market trends. The algorithm's accuracy improves over time, modeled by the function ( A(t) = frac{100}{1 + e^{-0.1(t - 50)}} ). There are two parts to the problem: first, finding the time ( t ) when the algorithm reaches 90% accuracy, and second, determining the break-even point for an investment that doubles the data processing speed.Starting with the first part. I need to find ( t ) such that ( A(t) = 90 ). So, I'll set up the equation:( 90 = frac{100}{1 + e^{-0.1(t - 50)}} )Hmm, okay. Let me solve for ( t ). First, I can rewrite this equation to isolate the exponential term. Subtract 90 from both sides? Wait, no, better to manipulate the equation step by step.Let me write:( frac{100}{1 + e^{-0.1(t - 50)}} = 90 )To solve for ( t ), I can first take reciprocals on both sides:( frac{1 + e^{-0.1(t - 50)}}{100} = frac{1}{90} )Wait, actually, maybe it's better to multiply both sides by the denominator:( 100 = 90(1 + e^{-0.1(t - 50)}) )Yes, that seems better. So:( 100 = 90 + 90e^{-0.1(t - 50)} )Subtract 90 from both sides:( 10 = 90e^{-0.1(t - 50)} )Divide both sides by 90:( frac{10}{90} = e^{-0.1(t - 50)} )Simplify ( frac{10}{90} ) to ( frac{1}{9} ):( frac{1}{9} = e^{-0.1(t - 50)} )Now, take the natural logarithm of both sides to solve for the exponent:( lnleft(frac{1}{9}right) = -0.1(t - 50) )Simplify the left side. Remember that ( lnleft(frac{1}{a}right) = -ln(a) ), so:( -ln(9) = -0.1(t - 50) )Multiply both sides by -1 to eliminate the negative signs:( ln(9) = 0.1(t - 50) )Now, solve for ( t ):First, divide both sides by 0.1:( frac{ln(9)}{0.1} = t - 50 )Calculate ( ln(9) ). I know that ( ln(9) ) is approximately 2.1972 because ( e^{2.1972} approx 9 ). Let me verify that:( e^{2} approx 7.389, e^{2.1972} approx 9 ). Yeah, that's correct.So:( frac{2.1972}{0.1} = t - 50 )Which is:( 21.972 = t - 50 )Add 50 to both sides:( t = 50 + 21.972 )So, ( t approx 71.972 ) weeks.Hmm, approximately 72 weeks. Let me check if that makes sense. The function ( A(t) ) is a logistic function, which has an S-shape. The midpoint is at ( t = 50 ) weeks, where the accuracy is 50%. The function approaches 100% as ( t ) increases. So, 90% accuracy should be a bit after the midpoint, which is 50 weeks. 72 weeks seems reasonable because the growth rate is 0.1, which is a moderate rate.Wait, let me plug ( t = 72 ) back into the original equation to verify:( A(72) = frac{100}{1 + e^{-0.1(72 - 50)}} = frac{100}{1 + e^{-0.1(22)}} = frac{100}{1 + e^{-2.2}} )Calculate ( e^{-2.2} ). ( e^{-2} approx 0.1353, e^{-2.2} approx 0.1108 ). So:( A(72) approx frac{100}{1 + 0.1108} = frac{100}{1.1108} approx 90.02% )That's very close to 90%, so ( t approx 72 ) weeks is correct.So, the first part answer is approximately 72 weeks.Moving on to the second part. The founder plans to invest 500,000 to double the data processing speed, which will halve the time needed to reach any accuracy level. So, if without the investment, it takes 72 weeks to reach 90%, with the investment, it will take 36 weeks.But wait, the question is about determining the minimum number of weeks after reaching 90% accuracy when the investment will break even. So, the investment costs 500,000, and once the algorithm reaches 90% accuracy, profits increase by 10,000 per week.Wait, but if the investment halves the time needed to reach 90%, does that mean that the time to reach 90% is 36 weeks instead of 72? So, the investment allows the algorithm to reach 90% accuracy in 36 weeks instead of 72 weeks.But the question is about the break-even time after reaching 90% accuracy. So, the investment is made now, and once the algorithm reaches 90% accuracy (in 36 weeks), the profits start increasing by 10,000 per week.Therefore, the break-even point is when the cumulative profits equal the investment cost.So, the investment is 500,000, and the weekly profit increase is 10,000. So, the number of weeks needed to break even is ( frac{500,000}{10,000} = 50 ) weeks.But wait, the question says "the minimum number of weeks after reaching 90% accuracy". So, it's 50 weeks after reaching 90% accuracy.But hold on, let me think again. The investment is made now, and the algorithm will reach 90% accuracy in 36 weeks. Then, starting from week 36, profits increase by 10,000 per week. So, the total profit after ( n ) weeks after reaching 90% is ( 10,000 times n ). We need this to equal 500,000.So, ( 10,000n = 500,000 ) implies ( n = 50 ) weeks.Therefore, the break-even occurs 50 weeks after reaching 90% accuracy.But wait, let me make sure I didn't misinterpret the question. It says, "the investment costs 500,000 and is expected to increase profits by 10,000 per week once the algorithm reaches 90% accuracy". So, the investment is a one-time cost, and the profit increase is a recurring 10,000 per week starting from when the algorithm reaches 90% accuracy.Therefore, the break-even time is the time after reaching 90% when the total profit increase equals the investment cost.So, yes, ( 500,000 / 10,000 = 50 ) weeks.But wait, another thought: does the investment affect the time to reach 90%? Yes, it halves the time, so instead of 72 weeks, it's 36 weeks. So, the algorithm reaches 90% in 36 weeks, and then from week 36 onwards, profits increase by 10,000 per week.Therefore, the break-even occurs 50 weeks after week 36, which is week 86. But the question asks for the minimum number of weeks after reaching 90% accuracy, so it's 50 weeks after week 36, which is 50 weeks.Wait, no, the question is phrased as: "the minimum number of weeks after reaching 90% accuracy when the investment will break even". So, it's 50 weeks after reaching 90% accuracy, regardless of when that happens.So, the answer is 50 weeks.But let me think again. If the investment is made now, and the algorithm reaches 90% in 36 weeks, then starting from week 36, each week brings in an extra 10,000. So, the total profit after ( n ) weeks is ( 10,000n ). We need ( 10,000n = 500,000 ), so ( n = 50 ) weeks.Therefore, 50 weeks after reaching 90% accuracy, the investment breaks even.Yes, that seems correct.So, summarizing:1. The algorithm reaches 90% accuracy at approximately 72 weeks.2. After investing, the time to reach 90% is halved to 36 weeks, and the break-even occurs 50 weeks after reaching 90%, so 50 weeks.But wait, the second part doesn't ask for the total time from now, but specifically the number of weeks after reaching 90% accuracy. So, it's 50 weeks.Therefore, the answers are approximately 72 weeks and 50 weeks.But let me double-check the first part calculation.Starting with ( A(t) = 90 ):( 90 = frac{100}{1 + e^{-0.1(t - 50)}} )Multiply both sides by denominator:( 90(1 + e^{-0.1(t - 50)}) = 100 )( 90 + 90e^{-0.1(t - 50)} = 100 )Subtract 90:( 90e^{-0.1(t - 50)} = 10 )Divide by 90:( e^{-0.1(t - 50)} = frac{1}{9} )Take natural log:( -0.1(t - 50) = ln(1/9) = -ln(9) )Multiply both sides by -1:( 0.1(t - 50) = ln(9) )So,( t - 50 = frac{ln(9)}{0.1} )Calculate ( ln(9) approx 2.1972 ), so:( t - 50 = 21.972 )Thus,( t = 50 + 21.972 approx 71.972 ), which is approximately 72 weeks. So, correct.Therefore, the first answer is approximately 72 weeks, and the second is 50 weeks after reaching 90% accuracy.Final Answer1. The algorithm reaches 90% accuracy after approximately boxed{72} weeks.2. The investment will break even after boxed{50} weeks following the achievement of 90% accuracy.</think>
❓:As a political science student at a college in Indiana, you are analyzing the voting patterns in different counties of the state to predict the outcome of the next gubernatorial election. You have access to a data set containing the number of registered voters and the percentage of voter turnout in each county during the last election. You want to build a predictive model to estimate voter turnout in the upcoming election based on historical data and some socioeconomic indicators.1. Data Analysis and Regression: Given a data set (D) of (n) counties where each county (i) has the following attributes: (R_i) (number of registered voters), (T_i) (voter turnout percentage from the last election), (I_i) (median household income), and (U_i) (unemployment rate). Develop a multiple linear regression model (T_i = beta_0 + beta_1 R_i + beta_2 I_i + beta_3 U_i + epsilon_i) to predict the voter turnout percentage (T_i). Determine the regression coefficients (beta_0, beta_1, beta_2, beta_3) using the given data set (D).2. Predictive Analysis: Using the regression model obtained in sub-problem 1, estimate the voter turnout percentage for a specific county where the number of registered voters is 50,000, the median household income is 55,000, and the unemployment rate is 4.2%.
🧠:<think>Okay, so I'm a political science student at a college in Indiana, and I need to analyze voting patterns in different counties to predict the outcome of the next gubernatorial election. I have a dataset with the number of registered voters, voter turnout percentage from the last election, median household income, and unemployment rate for each county. My task is to build a multiple linear regression model to predict voter turnout based on these variables.First, I need to understand the problem. The goal is to predict voter turnout, which is a percentage, so it's a continuous variable. The predictors are the number of registered voters, median income, and unemployment rate. I have to develop a model of the form:T_i = β0 + β1*R_i + β2*I_i + β3*U_i + ε_iWhere T_i is the voter turnout percentage, R_i is the number of registered voters, I_i is median household income, U_i is the unemployment rate, and ε_i is the error term.Since this is a multiple linear regression problem, I need to estimate the coefficients β0, β1, β2, β3 using the given data set D. To do this, I should probably use a statistical software or programming language like R or Python. But since I'm just thinking through the process, I'll outline the steps.First, I need to import the data set. Let's assume the data is in a CSV file with columns: County, R_i, T_i, I_i, U_i. I'll need to load this into my software.Next, I should perform some exploratory data analysis (EDA). This includes checking the distributions of each variable, looking for outliers, checking for multicollinearity between predictors, and seeing if there's any missing data. For example, if two predictors like income and unemployment are highly correlated, that could affect the regression coefficients.Then, I need to split the data into training and testing sets if I'm going to validate the model, but since the problem doesn't specify, maybe I can just use all the data for estimation.After that, I can fit the multiple linear regression model. In R, this would be something like lm(T_i ~ R_i + I_i + U_i, data = D). In Python, using statsmodels, it would be similar.Once the model is fit, I should check the summary statistics. This includes looking at the R-squared value to see how much variance is explained by the model, the p-values of the coefficients to see if they are statistically significant, and the standard errors.I should also check the assumptions of linear regression: linearity, independence, homoscedasticity, and normality of residuals. If any of these assumptions are violated, I might need to transform variables or consider a different model.For example, if the relationship between registered voters and turnout is not linear, I might need to log-transform R_i. Similarly, if the residuals are not normally distributed, I might need to consider a different approach.Assuming the model fits well, I can then use it to make predictions. The second part of the problem asks me to estimate the voter turnout for a specific county with R_i = 50,000, I_i = 55,000, and U_i = 4.2%.So, plugging these values into the regression equation:T_i = β0 + β1*(50,000) + β2*(55,000) + β3*(4.2)But wait, the units here might be an issue. The number of registered voters is in the tens of thousands, while income is in dollars. If the coefficients are estimated with these units, then the model can handle it, but sometimes scaling variables can help with interpretation.However, since the problem doesn't specify scaling or centering, I'll proceed as is.I should also consider whether the coefficients make sense. For example, does an increase in registered voters lead to higher or lower turnout? Intuitively, more registered voters might lead to higher absolute turnout, but as a percentage, it might not change much. So β1 could be small or even negative if more registered voters dilute the percentage.Median income: higher income might correlate with higher turnout, so β2 should be positive. Unemployment rate: higher unemployment might lead to lower turnout, so β3 should be negative.So, if after estimating the coefficients, β2 is positive and β3 is negative, that aligns with expectations. If not, I might need to reconsider the model or check for errors.Another thing to consider is whether the number of registered voters should be included as a predictor. Since turnout is a percentage, the number of registered voters might not directly affect the percentage, unless there's some diminishing returns or other factors. It might be more useful to include variables like population density, education levels, or political engagement, but since those aren't provided, I have to work with what I have.Also, I should check if the intercept β0 makes sense. It represents the expected turnout when R_i, I_i, and U_i are zero, which might not be meaningful in this context. But that's okay as long as the model is good for the range of data we have.Once I have the coefficients, I can plug in the specific values for the county. Let's say, hypothetically, the coefficients are:β0 = 40β1 = 0.0001β2 = 0.001β3 = -0.5Then, for R_i = 50,000, I_i = 55,000, U_i = 4.2:T_i = 40 + 0.0001*50,000 + 0.001*55,000 - 0.5*4.2= 40 + 5 + 55 - 2.1= 40 + 5 = 45; 45 +55=100; 100 -2.1=97.9But that seems too high for a voter turnout percentage. Maybe the coefficients are different. Perhaps β1 is negative, β2 is smaller, and β3 is more negative.Alternatively, maybe the coefficients are in different units. For example, if R_i is in thousands, then 50,000 would be 50, so β1 would be per thousand.Wait, that's a good point. If R_i is in the number of voters, which can be large, the coefficient β1 would be very small. Alternatively, if R_i is in thousands, the coefficient would be more manageable.But since the problem states R_i is the number of registered voters, not in thousands, I have to use it as is. So, for example, if R_i is 50,000, and β1 is 0.0001, then β1*R_i is 5. If β1 is 0.00001, then it's 0.5.So, the scale of the coefficients matters. It's important to ensure that the units are consistent.Another consideration is whether the model should include interaction terms or polynomial terms. For example, maybe the effect of income on turnout depends on the unemployment rate. But without more information, I'll stick to the linear model as specified.Also, I should check for heteroscedasticity. If the variance of the residuals is not constant, the standard errors might be incorrect, leading to unreliable hypothesis tests. I can use a Breusch-Pagan test or plot residuals vs fitted values to check this.If heteroscedasticity is present, I might need to use weighted least squares or robust standard errors.Additionally, I should check for influential observations using Cook's distance or leverage plots. Outliers can significantly affect the regression coefficients.After ensuring the model is valid, I can proceed to make the prediction.So, in summary, the steps are:1. Load and explore the data.2. Check for assumptions and preprocess if necessary.3. Fit the multiple linear regression model.4. Check model fit and assumptions.5. Use the model to predict voter turnout for the specific county.Now, since I don't have the actual data, I can't compute the exact coefficients. But if I were to write a step-by-step explanation, I would outline the process as above and then, assuming I have the coefficients, plug in the numbers.For the second part, the predictive analysis, I need to use the estimated coefficients. Let's say, hypothetically, after running the regression, I obtained the following coefficients:β0 = 30β1 = 0.00005β2 = 0.0005β3 = -0.4Then, plugging in the values:T_i = 30 + 0.00005*50,000 + 0.0005*55,000 - 0.4*4.2Calculating each term:0.00005*50,000 = 2.50.0005*55,000 = 27.5-0.4*4.2 = -1.68Adding them up:30 + 2.5 = 32.532.5 + 27.5 = 6060 - 1.68 = 58.32So, the predicted voter turnout would be approximately 58.32%.But I need to make sure that these coefficients make sense. For example, a higher income leading to higher turnout (positive β2) and higher unemployment leading to lower turnout (negative β3) align with expectations. The effect of registered voters (β1) is positive, meaning more registered voters are associated with higher turnout, which makes sense because more people are eligible to vote, so the percentage might not decrease, but in reality, it's possible that higher R_i could mean a lower percentage if not all registered voters turn out, but in this case, the coefficient is positive, so more registered voters are associated with higher turnout percentage, which might be counterintuitive. Maybe it's because more registered voters could indicate a more politically engaged population, hence higher turnout.Alternatively, if β1 were negative, it would suggest that more registered voters lead to lower turnout percentage, which could be due to dilution or other factors.In any case, the coefficients should be interpreted in the context of the data.Another thing to consider is whether the model accounts for other factors. For example, if a county has a strong political culture or recent political campaigns, those could affect turnout but aren't captured in the model. However, with the given variables, this is the best we can do.Also, the R-squared value would tell me how much of the variance in turnout is explained by the model. If it's low, the model isn't very predictive, and other variables might be important.In conclusion, after performing the regression analysis, I would use the coefficients to plug in the specific values and estimate the voter turnout percentage. The exact value depends on the coefficients obtained from the data.</think>
❓:An engineering student who appreciates the value of learning new languages for future career prospects is working on a project that integrates language processing algorithms with engineering data analysis. The student is developing a model that translates technical documents in multiple languages and then performs complex engineering calculations on the translated text.1. The student is using a Markov chain to model the probability transitions between words in the technical documents. Suppose the state space of the Markov chain is ( S = { w_1, w_2, ldots, w_n } ), where each ( w_i ) represents a unique word in the technical vocabulary. Let ( P ) be the transition matrix for the Markov chain, where ( P_{ij} ) represents the probability of transitioning from word ( w_i ) to word ( w_j ). Given that the transition matrix ( P ) is stochastic (each row sums to 1), derive the steady-state distribution ( pi ) of the Markov chain, where ( pi ) is a vector such that ( pi P = pi ) and ( sum_{i=1}^n pi_i = 1 ).2. After obtaining the steady-state distribution, the student uses it to weight the importance of different words in the engineering calculations. The student models the importance of each word using a function ( f(w_i) = pi_i cdot log(1 + gamma cdot text{freq}(w_i)) ), where ( text{freq}(w_i) ) is the frequency of word ( w_i ) in the document and ( gamma ) is a positive scaling constant. Assuming the frequencies ( text{freq}(w_1), text{freq}(w_2), ldots, text{freq}(w_n) ) are known, determine the total weighted importance ( I ) of all words in the document, defined as ( I = sum_{i=1}^n f(w_i) ).Use advanced linear algebra and probability theory to derive the steady-state distribution and calculate the total weighted importance based on the given function.
🧠:<think>Okay, so I have this problem about a Markov chain used in a language processing project. The student is trying to model the probability transitions between words in technical documents. I need to help derive the steady-state distribution and then calculate the total weighted importance of all words. Hmm, let's break this down step by step.First, part 1 is about finding the steady-state distribution π of the Markov chain. I remember that the steady-state distribution is a probability vector that remains unchanged when multiplied by the transition matrix P. So, mathematically, πP = π, and the sum of the components of π should be 1.Since P is a stochastic matrix, each row sums to 1, which is a key property. Now, to find π, I know that it's a left eigenvector of P corresponding to the eigenvalue 1. So, solving πP = π is essentially finding such a vector. But how do I actually compute it?I recall that for a finite Markov chain, if it's irreducible and aperiodic, the steady-state distribution exists and is unique. I wonder if the student's Markov chain meets these conditions. The problem doesn't specify, but since it's about language processing, I assume the chain is irreducible because any word can follow any other word in a document, and it's probably aperiodic because the period of each state is 1.Assuming that, the steady-state distribution can be found by solving the system of equations given by πP = π and the normalization condition Σπ_i = 1. This system can be written as (P^T - I)π = 0, where I is the identity matrix. So, we need to solve for π in this homogeneous system.But solving this directly might be complicated, especially for a large state space. Maybe there's a more straightforward way if the transition matrix has some special properties. For example, if the Markov chain is a regular Markov chain, then the steady-state distribution can be found by raising P to a high power and taking the limit as the number of steps goes to infinity. However, without knowing more about P, it's hard to say.Alternatively, if the chain is such that each state has the same steady-state probability, then π_i would be 1/n for all i. But that's only true for a uniform distribution, which might not be the case here.Wait, maybe the chain is a right stochastic matrix, so the steady-state distribution can be found by looking at the stationary distribution. If the chain is reversible, then detailed balance holds, meaning π_i P_{ij} = π_j P_{ji} for all i, j. But again, without knowing more about P, it's tricky.Perhaps the problem expects me to recognize that the steady-state distribution is the normalized leading left eigenvector of P. So, in practice, one would compute the eigenvalues and eigenvectors of P^T, find the eigenvector corresponding to eigenvalue 1, and then normalize it so that the sum of its components is 1.But since this is a theoretical problem, maybe I can express π in terms of P without computing it numerically. Let me think.Given that πP = π, we can write this as π(P - I) = 0, where I is the identity matrix. So, π is in the null space of (P - I). Since π must also be a probability vector, it's unique if the chain is irreducible and aperiodic.Therefore, the steady-state distribution π is the unique probability vector satisfying πP = π. So, in terms of derivation, I can state that π is the left eigenvector of P corresponding to the eigenvalue 1, normalized so that the sum of its components is 1.Moving on to part 2, the student uses the steady-state distribution π to weight the importance of each word with the function f(w_i) = π_i * log(1 + γ * freq(w_i)). The total importance I is the sum of f(w_i) over all words.So, I need to compute I = Σ_{i=1}^n π_i * log(1 + γ * freq(w_i)). Given that the frequencies are known, this is just a weighted sum where each weight is π_i and the term is log(1 + γ * freq(w_i)).But how do I calculate this? It seems straightforward once π is known. Since π is the steady-state distribution, we can compute each term individually and sum them up.However, without specific values for π_i and freq(w_i), I can't compute a numerical answer. So, perhaps the problem is just asking for the expression of I in terms of π and freq(w_i). In that case, I can write it as I = Σ π_i * log(1 + γ * freq(w_i)).But maybe there's a way to express this in terms of matrix operations or something else. Let me see.If I consider the vector f where each component is log(1 + γ * freq(w_i)), then I is the dot product of π and f. So, I = π · f.Alternatively, if I have π as a row vector and f as a column vector, then I = π f.But since the problem says to use advanced linear algebra and probability theory, maybe I need to express it in terms of expectation or something.Wait, since π is a probability distribution, I can think of I as the expected value of log(1 + γ * freq(w_i)) with respect to π. So, I = E_{π}[log(1 + γ * freq(w_i))].That might be a more elegant way to express it, using expectation notation.But the problem says to calculate the total weighted importance based on the given function. So, unless there's a specific formula or simplification, I think it's just the sum as given.Putting it all together, for part 1, the steady-state distribution π is the unique probability vector satisfying πP = π, found by solving the system (P^T - I)π = 0 with the normalization condition. For part 2, the total importance I is the sum over all words of π_i times the logarithm function of their frequencies.I think that's the extent of what I can derive without more specific information about P or the frequencies. So, summarizing:1. The steady-state distribution π is the left eigenvector of P corresponding to eigenvalue 1, normalized to sum to 1.2. The total weighted importance I is the sum of π_i multiplied by log(1 + γ * freq(w_i)) for each word.I should probably write this more formally in the final answer.Final Answer1. The steady-state distribution ( pi ) is the unique probability vector satisfying ( pi P = pi ) and ( sum_{i=1}^n pi_i = 1 ). It can be derived as the normalized left eigenvector of ( P ) corresponding to the eigenvalue 1.2. The total weighted importance ( I ) is given by ( I = sum_{i=1}^n pi_i cdot log(1 + gamma cdot text{freq}(w_i)) ).Thus, the answers are:1. ( boxed{pi} ) where ( pi ) is the normalized left eigenvector of ( P ) corresponding to eigenvalue 1.2. ( boxed{I = sum_{i=1}^n pi_i cdot log(1 + gamma cdot text{freq}(w_i))} )</think>
❓:Consider a country with a parliamentary electoral system where two parties, Party A and Party B, are the main contenders. The political science professor is analyzing the electoral outcomes based on gender-based voting trends. In a recent election, the total number of voters was 10 million, with a gender composition of 60% female and 40% male voters.1. The probability that a randomly selected female voter voted for Party A is 0.55, while the probability that a randomly selected male voter voted for Party A is 0.45. Calculate the probability that a randomly selected voter from the entire population voted for Party A.2. Assume that the gender-based preference for Party A can be modeled using a utility function ( U(g, p) = alpha g + beta p + gamma ), where ( g ) represents the gender factor (1 for female, 0 for male), ( p ) represents the political alignment factor (1 for Party A, 0 otherwise), and ( alpha, beta, gamma ) are constants. Given that the average utility for female voters is 0.6 and for male voters is 0.4, find the values of ( alpha, beta, gamma ) if these utilities are consistent with the described voting probabilities for Party A.
🧠:<think>Alright, so I have this problem about a parliamentary election with two parties, A and B. The country has a total of 10 million voters, with 60% female and 40% male. The first part asks for the probability that a randomly selected voter from the entire population voted for Party A, given that 55% of female voters and 45% of male voters chose Party A.Okay, let me break this down. First, I need to find the overall probability that a voter supported Party A. Since the voters are divided into two groups—female and male—with different probabilities of voting for Party A, I can use the law of total probability here.So, the total probability P(A) is equal to the probability of being female times the probability of voting for A given female, plus the probability of being male times the probability of voting for A given male. In formula terms, that would be:P(A) = P(Female) * P(A|Female) + P(Male) * P(A|Male)Given that 60% of voters are female, P(Female) is 0.6, and P(A|Female) is 0.55. Similarly, P(Male) is 0.4, and P(A|Male) is 0.45. Plugging these numbers in:P(A) = 0.6 * 0.55 + 0.4 * 0.45Let me compute that. 0.6 * 0.55 is 0.33, and 0.4 * 0.45 is 0.18. Adding those together gives 0.33 + 0.18 = 0.51. So, the probability that a randomly selected voter from the entire population voted for Party A is 51%.Wait, that seems straightforward. Let me just verify. 60% of 10 million is 6 million female voters, and 40% is 4 million male voters. 55% of 6 million is 3.3 million, and 45% of 4 million is 1.8 million. So total votes for Party A are 3.3 + 1.8 = 5.1 million. 5.1 million out of 10 million is indeed 51%. Yep, that checks out.Moving on to the second part. It says that the gender-based preference for Party A can be modeled using a utility function U(g, p) = αg + βp + γ, where g is 1 for female and 0 for male, p is 1 for Party A and 0 otherwise, and α, β, γ are constants. The average utility for female voters is 0.6, and for male voters is 0.4. We need to find α, β, γ such that these utilities are consistent with the voting probabilities.Hmm, okay. So, let's parse this. The utility function is linear in g and p. For female voters, g=1, and for male voters, g=0. For voters who choose Party A, p=1, and for those who choose Party B, p=0.But wait, the utility function is defined for each voter, but the average utility is given for each gender. So, for female voters, the average utility is 0.6, and for male voters, it's 0.4.So, let's think about how to model this. For female voters, the probability of voting for Party A is 0.55, so 55% of them have p=1, and 45% have p=0. Similarly, for male voters, 45% have p=1 and 55% have p=0.Therefore, the average utility for female voters can be calculated as:E[U | Female] = 0.55 * U(1,1) + 0.45 * U(1,0)Similarly, for male voters:E[U | Male] = 0.45 * U(0,1) + 0.55 * U(0,0)Given that the utility function is U(g,p) = αg + βp + γ, let's substitute.For female voters (g=1):E[U | Female] = 0.55*(α*1 + β*1 + γ) + 0.45*(α*1 + β*0 + γ)= 0.55*(α + β + γ) + 0.45*(α + γ)Similarly, for male voters (g=0):E[U | Male] = 0.45*(α*0 + β*1 + γ) + 0.55*(α*0 + β*0 + γ)= 0.45*(β + γ) + 0.55*γWe are told that E[U | Female] = 0.6 and E[U | Male] = 0.4. So, we can set up two equations:1) 0.55*(α + β + γ) + 0.45*(α + γ) = 0.62) 0.45*(β + γ) + 0.55*γ = 0.4So, now we have two equations with three variables: α, β, γ. Hmm, so we might need another equation or make an assumption to solve for all three.Wait, let's see. Maybe the utility function is defined such that the constants α, β, γ are set to make the average utilities as given. But with only two equations, we can't solve for three variables uniquely. So perhaps there's an additional assumption or condition we can use.Looking back at the problem statement: "the gender-based preference for Party A can be modeled using a utility function... Given that the average utility for female voters is 0.6 and for male voters is 0.4, find the values of α, β, γ if these utilities are consistent with the described voting probabilities for Party A."Wait, maybe the utility function is such that the difference in utilities between voting for A and B is what drives the probability. So, perhaps the utility difference is related to the probability.Alternatively, perhaps we can think of the utility function as a linear model where the probability of voting for A is a function of the utility. But the problem doesn't specify that, so maybe that's not the case.Alternatively, perhaps the utility function is such that the expected utility for each gender is given, and we have to find α, β, γ such that when we compute the expected utility for each gender, it's equal to 0.6 and 0.4 respectively.So, let's go back to the two equations we have:Equation 1: 0.55*(α + β + γ) + 0.45*(α + γ) = 0.6Equation 2: 0.45*(β + γ) + 0.55*γ = 0.4Let me simplify Equation 1 first.Expanding Equation 1:0.55α + 0.55β + 0.55γ + 0.45α + 0.45γ = 0.6Combine like terms:(0.55α + 0.45α) + 0.55β + (0.55γ + 0.45γ) = 0.6Which is:1.0α + 0.55β + 1.0γ = 0.6So, Equation 1 simplifies to:α + 0.55β + γ = 0.6Similarly, let's simplify Equation 2.Equation 2: 0.45β + 0.45γ + 0.55γ = 0.4Combine like terms:0.45β + (0.45γ + 0.55γ) = 0.4Which is:0.45β + 1.0γ = 0.4So, Equation 2 simplifies to:0.45β + γ = 0.4Now, we have two equations:1) α + 0.55β + γ = 0.62) 0.45β + γ = 0.4We can subtract Equation 2 from Equation 1 to eliminate γ.Subtracting Equation 2 from Equation 1:(α + 0.55β + γ) - (0.45β + γ) = 0.6 - 0.4Simplify:α + 0.55β + γ - 0.45β - γ = 0.2Which becomes:α + (0.55β - 0.45β) + (γ - γ) = 0.2Simplify further:α + 0.10β = 0.2So, Equation 3: α + 0.10β = 0.2Now, we have two equations:Equation 2: 0.45β + γ = 0.4Equation 3: α + 0.10β = 0.2But we still have three variables. So, we need another equation or make an assumption.Wait, perhaps the utility function is such that when p=0, the utility is just γ, or something like that? Or maybe we can set one of the variables to zero? The problem doesn't specify any additional constraints, so perhaps we can set one variable as a parameter.Alternatively, maybe the utility function is defined such that the intercept γ is zero? Or perhaps we can assume that when g=0 and p=0, the utility is zero? Let's see.If we assume that when g=0 and p=0, the utility is zero, then U(0,0) = α*0 + β*0 + γ = γ = 0. So, γ = 0.Is that a valid assumption? The problem doesn't specify, but sometimes in utility functions, the intercept is set to zero for simplicity. Let me try that.Assuming γ = 0, then Equation 2 becomes:0.45β + 0 = 0.4 => 0.45β = 0.4 => β = 0.4 / 0.45 ≈ 0.8889Then, Equation 3 becomes:α + 0.10β = 0.2 => α + 0.10*(0.8889) ≈ α + 0.0889 ≈ 0.2 => α ≈ 0.2 - 0.0889 ≈ 0.1111So, α ≈ 0.1111, β ≈ 0.8889, γ = 0.Let me check if this satisfies Equation 1.Equation 1: α + 0.55β + γ ≈ 0.1111 + 0.55*0.8889 + 0 ≈ 0.1111 + 0.4889 ≈ 0.6, which matches.Equation 2: 0.45β + γ ≈ 0.45*0.8889 + 0 ≈ 0.4, which also matches.So, that works. Therefore, the values are α ≈ 0.1111, β ≈ 0.8889, γ = 0.But let me express these as fractions to be precise.0.45β = 0.4 => β = 0.4 / 0.45 = 4/4.5 = 8/9 ≈ 0.8889Similarly, α + 0.10β = 0.2 => α = 0.2 - 0.10*(8/9) = 0.2 - 8/90 = 0.2 - 4/45 ≈ 0.2 - 0.0889 ≈ 0.11110.2 is 1/5, so 1/5 - 4/45 = (9/45 - 4/45) = 5/45 = 1/9 ≈ 0.1111So, α = 1/9, β = 8/9, γ = 0.Therefore, the values are α = 1/9, β = 8/9, γ = 0.Wait, let me verify again.With γ = 0, the utility function is U(g,p) = (1/9)g + (8/9)p.For female voters (g=1), the expected utility is:0.55*U(1,1) + 0.45*U(1,0) = 0.55*(1/9 + 8/9) + 0.45*(1/9 + 0) = 0.55*(1) + 0.45*(1/9) = 0.55 + 0.05 = 0.6, which is correct.For male voters (g=0), the expected utility is:0.45*U(0,1) + 0.55*U(0,0) = 0.45*(0 + 8/9) + 0.55*0 = 0.45*(8/9) = (0.45)*(0.8889) ≈ 0.4, which is correct.Yes, that works. So, the values are α = 1/9, β = 8/9, γ = 0.Alternatively, if we don't assume γ = 0, we might have infinitely many solutions, but since the problem asks for specific values consistent with the described voting probabilities, and given that the average utilities are given, it's reasonable to set γ = 0 to pin down the solution.Therefore, the solution is α = 1/9, β = 8/9, γ = 0.</think>