Question

In a sample of 200 books, 26 books contained at least one punctuation error. The sampling method had a margin of error of 0.03. What is the interval estimate for the proportion that would have at least one punctuation error in the form (lower limit, upper limit) ?

Answer 1

confidence interval =(0.10,0.16)

Explanation:

Given that sample proportion was

26/200 =0.13 for a sample size of 200

Margin of error is given as 0.03

We know that confidence interval is one which is calculated as sample proportion ±Margin of error

Here sample proportion=0.13

Margin of error = 0.03

Hence

confidence interval lower limit = 0.13-0.03 = 0.10

Confidence interval upper limit = 0.13+0.03 = 0.16

Hence confidence interval =(0.10,0.16)