The manager of an online shop wants to determine whether the mean length of calling time of its customers is significantly more than 3 minutes. A random sample of 100 customers was taken. The average length of calling time in the sample was 3.1 minutes with a standard deviation of 0.5 minutes. At a 0.05 level of significance, it can be concluded that the mean of the population is:
A) significantly greater than 3.
B) not significantly greater than 3.
C) significantly less than 3.
D) not significantly different from 3.10.

Question

Quizplus · Accepted Answer

The hypothesis test in question is a one-tailed test, aiming to determine if the mean calling time is significantly greater than 3 minutes. Given the sample mean (3.1 minutes), sample size (100), and standard deviation (0.5 minutes), a t-test or z-test can be conducted (with large sample sizes, they yield similar results). The result indicating a mean significantly greater than 3 minutes, at a 0.05 level of significance, supports option A.

The Manager of an Online Shop Wants to Determine Whether