Nancy believes that the average running time of movies is equal to 140 minutes. A sample of 4 movies was taken and the following running times were obtained. Assume the population of the running times is normally distributed.

150 150 180 170

a. Compute the sample mean and the standard deviation.

b. State the null and alternative hypotheses.

d. Calculate the test statistic.

d. Using the critical value approach, test the hypotheses at the 10% level of significance.

e. Using the p-value approach, test the hypotheses at the 10% level of significance.