Question

A customer service phone line claims that the wait times before a call is answered by a service representative is less than 3.3 minutes. In a random sample of 62 calls, the average wait time before a representative answers is 3.26 minutes. The population standard deviation is assumed to be 0.14 minutes. Can the claim be supported at α=0.08?

No, since test statistic is not in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is not supported

Yes, since test statistic is not in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is supported

Yes, since test statistic is in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is supported

No, since test statistic is in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is not supported

Answer 1

Solution :

= 3.3

= 3.26

= 0.14

n = 62

This is the left tailed test .

The null and alternative hypothesis is

H0 :   = 3.3

Ha : < 3.3

Test statistic = z

= ( - ) / / n

= (3.26 - 3.3) / 0.14 / 62

= -2.250

P (Z < -2.250) =0.0122

P-value = 0.0122

= 0.08

The left tailed test critical value = -1.405

0.0122< 0.08

Yes, since test statistic is in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is supported