Question

Last year a company received 50 complaints concerning carpet installation. The data in the accompanying table represents the number of days between the receipt of a complaint and the resolution of the complaint. Complete parts​ (a) through​ (d).

55 55 7 31 136 31 30 151 2 119

77 76 22 15 10 128 107 111 19 85

91 40 31 30 10 15 6 162 33 37

25 29 22 5 11 10 15 18 10 12

22 58 40 26 33 25 26 24 32 66

The supervisor claims that the mean number of days between the receipt of a complaint and the resolution of the complaint is days. At the level of​ significance, is there evidence that the claim is not true​ (that is, that the mean number of days is different from 20​)?

State the null and alternative hypotheses.

Determine the test statistic.

Find the​ p-value.

State the conclusion.

b. What assumption about the population distribution is needed in order to conduct the t test in​ (a)?

Construct a normal probability plot to evaluate the assumption made in​ (b). Choose the correct graph below.

Answer 1