更新1:
what is the stadard deviation be so that 99% of the shafts will meet specification ?
normal distribution?
2017-11-28 10:06 pm
shafts manufactured for use in optical storage devices havediameters that are normally distributed with mean 0.652 cm andstandard deviation 0.003cm. the specification for the shaftdiameter is0.650 +- 0.005cm. a) what proportion of the shafts manufactured by thisprocess meet the specifications? b) the process mean can be adjusted through calibration.if the mean is set to 0.650cm,
回答 (1)
2017-11-28 10:29 pm
✔ 最佳答案
0.650-0.005 = 0.6450.650+0.005 = 0.655
a)
μ = 0.652
σ = 0.003
standardize x to z = (x - μ) / σ
P( 0.645 < x < 0.655) = P[( 0.645 - 0.652) / 0.003 < Z < ( 0.655 - 0.652) / 0.003]
P( -2.3333 < Z < 1) = P( z < 1) - P( z < -2.3333) = 0.8413 - 0.0009 = 0.8404 (proportion meeting the specification)
(From Normal probability table)
b)
mean = 0.650
From the normal table, P( -2.575 < z < 2.575) = 0.99
z = (x - μ) / σ
2.575 = (0.655 - 650) / σ
2.575 σ = .005
σ = .005/2.575 = 0.00194
收錄日期: 2021-04-24 00:57:44
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20171128140631AAvudbK