四次测试小丽每分钟做仰卧起坐的次数分别为：50、45、48、47，这

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问题填空题

四次测试小丽每分钟做仰卧起坐的次数分别为：50、45、48、47，这组数据的中位数为_______.

答案

47.5

中位数是指把一组数据按照大小依次排列后，其最中间的一个数或两个数的平均数。这四个数的最中间的两个数是47和48，它们的平均数是47.5.

补全对话，情景问答

补全对话。

Salesman: Good morning, madam. 1. _____

Woman: I'm looking for a pair of shoes for my daughter as her birthday present.

There's a pair of red shoes in the shop window. I think she'll like them.

(The salesman shows the woman a pair of red shoes.)

S: They look very nice.

W: I don't think they are big enough. 2. _____

S: Size five, madam.

W: They're too small. Could I have a larger size?

S: 3. _____

(He shows the woman another pair of shoes)

S: 4. _____ They're Size six. Are they big enough?

W: Yes. They're the right size. 5. _____

S: Twelve pounds, madam.

W: I'll take them.

S: Here you are. Thanks.

A. Certainly.

B. Can I help you?

C. How much are they?

D. What about this pair?

E. What size are they?

1._____ 2._____ 3._____ 4._____ 5._____

问答题简答题

阐述系统测试的定义及内涵。