Author Question: A house cleaning service claims that it can clean a four bedroom house in less than 2 hours. A ... (Read 803 times)

tiara099 · **on:** Jun 24, 2018

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 ).

Question 2

Madam Helga claims to be psychic. A national TV talk personality plans to test her in a live TV broadcast. The process will entail asking Madam Helga a series of 20 independent questions with yes/no answers.

The questions would be of the nature that she could not have any way of knowing the answer from prior knowledge. She will be considered psychic if she correctly answers more than a specified number (called the cut-off) of the questions. The cut-off must be set so that the chance of guessing that number or more is no greater than 5 percent. The cut-off value should be:A) 12
B) 14
C) 10
D) Can't be determined without more information.