根据句意及首字母提示补全单词

1. Here is a t______ racket.

2. They play football e ______day.

3. I don't w ______ TV in the evening.

4. We have many c ______: volleyball, basketball, ping--pong .

5. Let's p______ soccer.

6. Sue ______ (not have) a great sports collection.

7. —Let's watch TV.  

    —That ______(sound) fun.

8. He _______ (have) a tennis racket.

9. —______she ______(have) a phone?  

    —No, she doesn't.

一个观察值与均值之间的差值被称为（）。

A、方差

B、标准差

C、离均差

D、均差