SOLUTION: Suppose a geyser has a mean time between eruptions of 74 minutes. If the interval of time between the eruptions is normally distributed with standard deviation 21 minutes​, what

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Question 1156355: Suppose a geyser has a mean time between eruptions of 74 minutes. If the interval of time between the eruptions is normally distributed with standard deviation 21 minutes​, what is the probability that a random sample of 26 time intervals between eruptions has a mean longer than 83 ​minutes?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
This is a z-test since we know the sd
z=(x bar-mean)/sigma/sqrt(n)
>(83-71)/21/sqrt(26)
>2.91
probability is 0.0018