A house cleaning service claims that it can clean a four bedroom house in less than 2 hours. A sample of n = 16 houses is taken and the sample mean is found to be 1.97 hours and the sample standard deviation is found to be 0.1 hours. Using a 0.05 level of significance the correct conclusion is: A) reject the null because the test statistic (-1.2) is the critical value (-1.7531). C) reject the null because the test statistic (-1.7531) is the critical value (-1.7531).

Question

A house cleaning service claims that it can clean a four bedroom house in less than 2 hours. A sample of n = 16 houses is taken and the sample mean is found to be 1.97 hours and the sample standard deviation is found to be 0.1 hours. Using a 0.05 level of significance the correct conclusion is: A) reject the null because the test statistic (-1.2) is < the critical value (1.7531). B) do not reject the null because the test statistic (1.2) is > the critical value (-1.7531). C) reject the null because the test statistic (-1.7531) is < the critical value (-1.2). D) do not reject the null because the test statistic (-1.2) is > the critical value (-1.7531).

Quizplus · Accepted Answer

The test statistic (-1.2) being greater than the critical value (-1.7531) indicates that the observed sample mean is not significantly less than the hypothesized mean (2 hours) at the 0.05 level of significance, leading to the conclusion not to reject the null hypothesis.

A House Cleaning Service Claims That It Can Clean a Four