Question

The population mean and standard deviation are given below. Find the required probability and determine whether the given sample mean would be considered unusual. For a sample of n=68, find the probability of a sample mean being less than 20.6, if u=21 and σ=1.31

For a sample of n=68, the probability of a sample mean being less than 20.6 if μ=21 and σ=1.31 is ________

(Round to four decimal places as needed)

Answer 1

here, sample size (n) = 68 >30, so, we can say that the sample mean will follow normal distribution with :-

the probability of a sample mean being less than 20.6 is:-

[ using standard normal table ]

decision:-

the probability is = 0.0059 < 0.05..

Hence, we can say that the given sample mean would be considered unusual.

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