Question

The mean number of words per minute (WPM) read by sixth graders is 86 with a variance of 225. If 44 sixth graders are randomly selected, what is the probability that the sample mean would differ from the population mean by less than 3.71 WPM

Answer 1

P(X<=x) = 1 + 5.486 = 6.486

The z-score of the information given is,

z = (x - µ )/ σ

Where,

µ = mean

σ = standard deviation

From the information given,

x = 3.71

µ = 86

σ  = √225 = 15

hence,

z = (3.71 - 86)/15 = -5.486

thus,

P(X<=x) = 1 + 5.486 = 6.486

hence , P(X<=x) = 1 + 5.486 = 6.486

Learn more about variance here brainly.com/question/9304306

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