In a small town in early 2016, amongst the voting population: 80% of Democrats,
ID: 3041901 • Letter: I
Question
In a small town in early 2016, amongst the voting population: 80% of Democrats, 14% of Republicans and 54% of Independents approve of Obama's job performance (#'s taken from US population data polls, see 1 and 2). In this small town: 30% are Democrat, 28% are Republican and 42% are Independent (taken and adjusted to make sure they add to 100% from population proportion data 3). (a) 2 points What proportion of voters in this small town think the president is doing a good job (approve of Obama's job performance)? (b) 2 points A randomly chosen voter thinks the president is doing a good job. What is the probability this voter is Democrat?Explanation / Answer
a) Proportion of voters think President is doing a good job = 0.30*0.80+0.28*0.14+0.42*0.54 = 0.506
b) P( Democrat/President is doing good job = (0.30*0.80)/0.506 = 0.474 ( Rounded to three decimal places)