Normal distribution with mean 73 & standard deviation 8; find:
Formula: Z = (X - u)/ o { u=mean; o=standard dev.
(i) prob. of getting 91 OR less scores.
Assumed to be: P (X < = 91)
(ii) prob. of getting less than 91 scores.
Assumed to be: P (X < 91)
So, calculations & answers of (i) & (ii) should be different? Right?
Please calculate by applying the formula in detailed steps. TKS!
Statistics
2011-10-13 4:30 am
回答 (1)
2011-10-13 4:39 am
✔ 最佳答案
The value of (i) and (ii) should be the same as P(X = a) = 0 when x follows a continuous distribution.Asnwer: (i) and (ii) 0.987776
(i) P(X <= 91)
= P[(X - 73)/8 <= (91 - 73)/8]
= P(Z <= 2.25)
= 0.987776
(ii) Similar as (i) but replace 'less than or equal to' by 'less than'
收錄日期: 2021-04-13 18:18:32
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