SOLUTION: We wish to estimate what percent of adult residents in a certain county are parents. Out of 500 adult residents sampled, 40 had kids. Based on this, construct a 90% confidence inte

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Question 1191260: We wish to estimate what percent of adult residents in a certain county are parents. Out of 500 adult residents sampled, 40 had kids. Based on this, construct a 90% confidence interval for the proportion
π
of adult residents who are parents in this county.
Provide the interval estimate in the form:
Sample Proportion
±
Margin of Error
Give your answers as decimals, rounded to three places.
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
90% half-interval is z(0.95)*sqrt(p(1-p)/n), where p=40/500=0.08
=1.645*sqrt(0.08*0.92/500)
=1.645*0.0121
=0.0200
interval is 0.080 +/- 0.020