At a large hospital the average number of new hospital-acquired infections is 16.5 infections per week. Hospital staff decides to implement new procedures to reduce the number of hospital-acquired infections. Four months after the new procedures were implemented, an SRS of 9 weeks found an average of 15.3 infections per week. Suppose hospital-acquired infections are normally distributed with a known standard deviation()of 2.1 infections per week. At the 5% level of significance, is there evidence the new procedures reduced the rate of hospital-acquired infections?

(a) (4 pts.) State your hypotheses using mathematical notation (symbols).

(b) (4 pts.) Calculate the value of the test statistic.

(c) (4 pts.) Determine the p-value.

(d) (4 pts.) State your conclusion in terms of the problem.