A medical doctor states that the mean age of his patients is 47 years. A random sample of 50 of his patients was selected and their age was recorded. The ages were inputted into MINITAB for analysis. Exhibit 1 below shows the results of an analysis carried out on the data obtained:

Exhibit 1

Test of mu = 47 vs mu not = 47

The assumed sigma = 18.0

Variable N Mean StDev SE Mean Z P

Age 50 45.6 18.1 2.6 * **

(a) State the null and the alternative hypotheses for this test.

(b) Calculate the missing Z value '*'.

(c) Determine the missing P value '**'. Interpret your answer for the P value.

(d) Explain the term 'level of significance'.

(e) If you were the student conducting this test, what would you conclude and why?