Question

In an election, the population consists of the people who voted. Although there is overall data on how the population voted, there is no population data on how specific individuals voted.
Exit polls are small surveys that use random sampling to ask voters questions immediately after they have voted. CNN conducted an exit poll in Texas after the 2016 presidential election. They asked a variety of questions, including whom the person voted for and their age.

One age group of interest was 25–29 years. Although the proportion, , of voters ages 25–29 who voted for Donald Trump is not known, it does exist. Assume for this exercise that =0.412. Also assume that the exit poll consisted of 226 voters ages 25–29 .

Determine the value of such that in 95% of all samples of size 226, the proportion of Trump voters would be within of the population proportion, =0.412.

Answer 1

Answer:

Answer:

P(A) = 0.39

Step-by-step explanation:

We are given;

P(W|A) = 0.7

P(W|A^c ) = 0.3

We are told that 60% of the respondents said they voted for A. Thus;

P(A|W) = 60% = 0.6

Now, using the principle of drawing lots, we can be able to find the probability of the event that they are willing to participate in the exit poll which is P(W).

Thus;

P(W) = [P(W|A) × P(A)] +[P(W∣A^c) × P(A^c)]

Now, P(A^c) can be expressed as 1 - P(A)

Thus, we now have;

P(W) = [P(W|A) × P(A)] + [P(W∣A^c) × (1 - P(A)]

Plugging in the relevant values gives;

P(W) = 0.7P(A) + 0.3(1 - P(A))

P(W) = 0.7P(A) + 0.3 - 0.3P(A)

P(W) = 0.3 + 0.4P(A)

Now,using Baye's theorem, we can find an expression for P(A|W)

Thus;

P(A|W) = [P(A ∩ W)]/P(W)

This can be further expressed as;

P(A|W) = [P(A) × P(W|A)]/P(W)

Plugging in relevant values, we have;

0.6 = 0.7P(A)/(0.3 + 0.4P(A))

Cross multiply to get;

0.6(0.3 + 0.4P(A)) = 0.7P(A)

0.18 + 0.24P(A) = 0.7P(A)

0.18 = 0.7P(A) - 0.24P(A)

0.46P(A) = 0.18

P(A) = 0.18/0.46

P(A) = 0.39

Step-by-step explanation:

braniest