TextRequest reports that adults 18–24 years old send and receive 128 texts every day. Suppose we take a sample of 25–34-year-olds to see if their mean number of daily texts differs from the mean for 18–24-year-olds reported by TextRequest. 

a. State the null and alternative hypotheses we should use to test whether the population means a daily number of texts for 25–34-year-olds differs from the population daily mean a number of texts for 18–24-year-olds. 

b. Suppose a sample of thirty 25–34-year-olds showed a sample mean of 118.6 texts per day. Assume a population standard deviation of 33.17 texts per day and compute the p-value. 

c. With α = .05 as the level of significance, what is your conclusion? 

d. Repeat the preceding hypothesis test using the critical value approach.