数学课前练习

1. 设随机变量\(X, Y\)满足：\(Y = 3X - 1\)，\(X \sim B\left(2, \displaystyle \frac{1}{3}\right)\)，则\(D(Y) =\)

A. 4

B. 5

C. 6

D. 7

2. 随机抛掷一枚质地均匀的硬币5次，恰好出现3次正面向上的概率为( )

A. \(\displaystyle \frac{1}{8}\)

B. \(\displaystyle \frac{5}{16}\)

C. \(\displaystyle \frac{3}{5}\)

D. \(\displaystyle \frac{5}{8}\)

3. 袋中装有2个红球，2个黄球，有放回地抽取3次，每次抽取1球，则3次中恰有2次抽到黄球的概率是( )

A. \(\displaystyle \frac{3}{8}\)

B. \(\displaystyle \frac{1}{4}\)

C. \(\displaystyle \frac{3}{16}\)

D. \(\displaystyle \frac{5}{16}\)