Use the following information to answer questions 17 and 18: The manager for the sales department for a large company has noticed a decrease in sales. In an attempt to increase the sales performance, he launched a training program to his employees. To evaluate the program, he selected a random sample of 6 employees and recorded the sales before and after the program. Below are the results. Employee Before 17. What are the difference mean (before- after) and standard deviation? * O d=-1.75ande='l.75 O d=-1.67 ande=2.33 O d=1.67and8d=1.75 O d=-1.67ande='l.75 18. State the null and the alternate hypothesis: * 0 Ho: pd s 0 and H1:pd >0 0 H0: pd 2 0 and H1:pd