The dollar value of orders placed through a particular store catalog is found to be normally distributed with a standard deviation of 21.58. A sample of 30 orders averaged 81.25. What is the 90 confidence interval around this sample mean?
A) 81.25 21.58
B) 81.25 10.79
C) 81.25 12.15
D) 81.25 6.48
Question 2
What is the probability that in a particular month the office receives more than 310 orders?
A) 0.7823
B) 0.2826
C) 0.7174
D) 0.2177