Denise made 9 sales calls on Monday, 6 sales calls on Tuesday, 7 sales calls on Wednesday, 9 sales calls on Thursday, and 11 sales calls on Friday. What was the average (arithmetic mean) number of sales calls that Denise made for these 5 days?
8.4
8.6
8.8
9.0
9.2
平均值不要求是整数
我真的是想的太多了,以为call只能是整数。。。。算出来8.4,选了9!