The mass of a grade A steel cylinder manufactured in a factory follows a normal distribution with m
The mass of a grade A steel cylinder manufactured in a factory follows a normal distribution with mean 2.2 kg and standard deviation 250 g.The mass of a grade B steel follows a normal distribution with mean 1.5 kg and standard deviation 140 g.Determine the probability that
求the total mass of 6 grade A steel is more than that of 7 grade B steel,all chosen at random.
The mass of a grade A steel cylinder manufactured in a facto
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解决时间 2021-07-31 23:15
- 提问者网友：ミ烙印ゝ
- 2021-07-31 04:33
最佳答案
- 五星知识达人网友：一叶十三刺
- 2021-07-31 05:17
A 服从高斯分布G(2.2,0.25)；B 服从高斯分布G(1.5,0.14).
定义
Y = 6A-7B,
则Y服从高斯分布G(2.7,0.71568).
所以
P（Y > -2.7） = P (Y/0.71568 > -3.77) = 0.999918.
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