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Where’s Egypt? In a Pew Research poll, 287out of 522randomly selected U.S. men were able to identify Egypt when it was highlighted on a map of the Middle East. When520 randomly selected U.S. women were asked, 233 were able to do so.

a. Construct and interpret a 95% confidence interval for the difference in the true

proportion of U.S. men and U.S. women who can identify Egypt on a map.

b. Based on your interval, is there convincing evidence of a difference in the true

proportions of U.S. men and women who can identify Egypt on a map? Justify your

answer.

Short Answer

Expert verified

a. Confidence Interval is (-0.0191,0.1017).

b. Yes, there is evidence of difference in true proportion of US men and women who can identify Egypt on map or not.

Step by step solution

01

Given Information

It is given that x1=287

x2=233

n1=522

n2=520

c=95%=0.95

02

Calculating Confidence Interval

The three conditions are:

Random: Samples are independent random samples.

Independent: 522US men are less than 10%of population. Same is true for women.

Normal: Success in two samples are 287,233and failures are 235,287. All are greater than ten.

All conditions are satisfied.

Sample Proportion: p^1=x1n1=287522=0.5498

p^2=x2n2=233520=0.4481

Confidence Interval:

p^1-p^2-zα/2×p^11-p^1n1+p^21-p^2n2

=(0.5498-0.4481)-1.96×0.5498(1-0.5498)522+0.4481(1-0.4481)520

≈-0.0191

and p^1-p^2+zα/2×p^11-p^1n1+p^21-p^2n2

=(0.5498-0.4481)+1.96×0.5498(1-0.5498)522+0.4481(1-0.4481)520

≈0.1017

The confidence interval is(-0.0191,0.1017)

03

To check if there is evidence of difference in true proportion of US men and women who can identify Egypt on map or not. 

As the confidence interval (-0.0191,0.1017)does not contain zero. It is unlikely that population proportions are equal.

So, there is evidence of difference in true proportion of US men and women who can identify Egypt on map or not.

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