Question

MEDAL IF SOLVED CORRECTLY!!!!!!!!!!!! HELP!?

Suppose that a customer service center claims that the telephone calls it receives last 113 seconds on average with a standard deviation of 9 seconds of you took a sample of 324 telephone calls which of the following mean times would b within the 95% confidence interval?

A 114.5
B 113.5
C 115.5
D 116.5

Answer 1

The 95% confidence interval is:
\[113\pm1.96\frac{9}{\sqrt{324}}\]
When you calculate the confidence interval, you can select the correct answer.