A statistics practitioner is n the process of testing to determine whether there is enough evidence to infer that the population mean is different from 180. She calculated the mean and standard deviation of a sample of 200 observations as x-bar equals 175 and s = 22.
a. Calculate the value of the test statistic required to determine whether there is enough evidence at the 5% significance level. Use Excel to calculate the appropriate p-value as well.
b. Repeat part (a) with s = 45.
c. Repeat part (a) with s = 60.
d. Discuss what happens to the t statistic and the p-value when the standard deviation increases.