SOLUTION: The amount of time required for an oil and filter change on an automobile is normally distributed with a mean of 45 minutes and a standard deviation of 10 minutes. A random sample

Question 1182722: The amount of time required for an oil and filter change on an automobile is normally distributed with a mean of 45 minutes and a standard deviation of 10 minutes. A random sample of 16 cars is selected. What is the probability that the sample mean will be between 39 and 48 minutes?
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
The sd of the sampling distribution of size 16 has mean 45 and sd 10/sqrt(16), or sd=2.5
z is between (39-45)/2.5=-2.4 and (48-45)/2.5=1.2
this has probability of 0.8767

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