A machine produces 3 inch nails. A sample of 100 nails is selected, and it is found that 25 are shorter than 3 inches. Find a 95% confidence interval on the proportion of all such nails that are shorter than 3 inches

p=.25 because 25/100 = .25

Therefore, q=1-p=.75

The error of estimate is given by the formula:

E=z\sqrt{\frac{pq}{n}}

The z score for 95% CI is z=1.96.

Now, plug your values into the formula.

Add and subtract that value from .25 to create your confidence interval.

It should be written as p-E<p+E