Suppose a consumer group asked 18 consumers to keep a yearly log of their shopping practices and that the following data represent the number of coupons used by each consumer over the yearly period. Calculate the following descriptive statistics (two decimal places):

81 110 100 21 66 90 68 105 94 70 70 78 70 60 47 66 82 85

a) The sample mean is: b) The sample standard deviation is: