Let W be a random variable that is normally distributed. If the probability of W being less than 40 is 1/6
and 70 is two standard deviations above the mean, which of the following is the best estimate for the mean of W?
How do I do this?
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since 1/6 is 16% that is 2 sd below the mean so
40= mean-2SD
70=mean+2SD
solve for mean
mean=55
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@prakithgre, wouldn’t 1/6 or 16% be 1 st dev below mean
So approximately:
mean - st dev = 40
mean + 2 st dev = 70
2mean - 2 st dev = 80
3 mean = 150
mean = 50
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Yup sorry my bad your solution is correct
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