# statistics

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a random sample of 100 college students is taken from the student body of a large university. assume that a population mean of 20 hours and a population standard deviation of 15 hours describes the weekly study estimates for the entire student body. About 68 percent of the sample means in this sampling distribution should be between?

• statistics -

68% are approximately within mean ± 1 SD

Z = ±1 = (score - mean)/SEm

SEm = SD/√(n-1) = approx. SD/10

Insert values in above Z equation to get scores.

• statistics -

consider a normal distribution with mean 27 and standard deviation 6. What is the probability a value selected at random from this distribution is great than 27?

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