Question: A small brokerage firm reported that their mean daily sales volume for the past year (2009) was $172,500 with a known standard deviation of $19,300 for the year’s data. The firm’s operations manager has noticed that daily sales seem to be decreasing this year. A random sample of 30 daily sales had an average value of $164,100.

a. What is the appropriate null hypothesis?

b. What is the probability value/

c. What value must the p value be smaller than if we reject the null hypothesis?