Posted by **Teddy** on Sunday, May 15, 2011 at 11:22pm.

In a certain city, there are 10,000 persons age 18 to 24. A simple random sample of

500 such persons is drawn, of whom 200 turn out to be currently enrolled in college. Find a 90%

conŻdence interval for the percentage of persons age 18 to 24 in the city who are attending college.

- Statistics -
**MathGuru**, Monday, May 16, 2011 at 5:35pm
Try using a binomial proportion CI formula:

CI90 = p + or - 1.645(√pq/n)

...where p = proportion in the problem, q = 1 - p, n = sample size, √ = square root, and + or - 1.645 represents 90% CI using a z-table.

Your data:

p = 200/500

q = 1 - p

n = 500

Convert all fractions to decimals. Substitute values into the formula and determine the confidence interval.

I hope this will help get you started.

- Statistics -
**Ashley**, Monday, November 21, 2011 at 11:56pm
500.12

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