Question

求教三道概率论和数理统计题!(务请给出解题思路和大致过程,感激不尽!)

Answer 1

设X是所抽取50件中次品数,如果次品率为0.99,于是X~B(50,0.01)

P(X>=2)=1-P(Xxa)=0.05,查表得xa=12.592

将样本观测值带入计算

X^2=（36-34)^2/34+(23-34)^2/34+(29-34)^2/34+(31-34)^2/34+(34-34)^2/34+(60-34)^2/34+(25-34)^2/34

=26.94117647>12.592=xa

否定H0,即认为交通事故的发生与周几有关.

3）由P(X>90)=359/10000,得(90-u)/σ=1.8;

P(X