# Estimation, Confidence Interval for proportions

A random sample of 90 prisoners in a large state prison revealed that 20% were college graduates. Find the 99% confidence interval in the population sampled for the percentage of prisoners who are college graduates.

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#### Solution Preview

p=proportion of college graduates= 20.00%

q=1-p= 80.00%

n=sample size= 90

s p=standard error of proportion= square root of (pq/n)= 4.22% = square root of ( 20.% * ...

#### Solution Summary

The solution calculates the 99% confidence interval in the population sampled for the percentage of prisoners who are college graduates.

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