Normal Distribution 題目 @ szw52ts91l的部落格

標題:

Normal Distribution 題目

發問:

2.Consider a standard normal variable Z. Find c such that a)P(Z < c) = 0.8 b)P(Z < c) = 0.27 c)P(0 < Z < c) = 0.311 點做更新: find 0.8 from the table and c = 0.8416 我唔知點樣睇個table 更新 2: find 0.8 from the table and c = 0.8416 我唔知點樣睇個table 0.8416係起1.0 個行更新 3: this is answer 2.a) 0.84b) –0.61c) 0.88 比個process我 thx

最佳解答:

2. the left hand side column and top row of the normal distribution table is the Z value the value inside the table represent the probability a) since P(Z < c) is more than 0.5 it should be consider the inverse part P(Z < c) = 0.8 1 - P(Z > c) = 0.8 P(Z > c) = 0.2 c = 0.84 find the probability about 0.2 from the table, the Z value of this probability is 0.84 b) P(Z < c) = 0.27 c = -0.61 find the probability about 0.27 from the table, the Z value of this probability is 0.61 since P(Z < c) is less than 0.5, the Z value is negative c) P(0 < Z < c) = 0.311 0.5 - P(Z > c) = 0.311 P(Z > c) = 0.189 c = 0.88

其他解答:

look at the inverse normal function table, a)inverse of [Q] (p) = z find 0.8 from the table and c = 0.8416 b)invese of p(0.27) = -p(0.73) c = -0.6128 i am not sure about the third one, should be something like 0.5 - -p(0.689) =0.5 - 0.4930