Critical part failures in NASCAR vehicles.The Sport Journal(Winter, 2007) published a stud...

Critical part failures in NASCAR vehicles.The Sport Journal(Winter, 2007) published a study of critical part failures at NASCAR races. The researchers found that the time x (in hours) until the first critical part failure has a skewed distribution with μ = .10 and σ = .10. Now, consider a random sample of n= 50 NASCAR races and let x represent the sample mean time until the first critical part failure.

a. Find E() and Var().

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b. Although x has a skewed distribution, the sampling distribution of   is approximately normal. Why?

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c. Find the probability that the sample mean time until the first critical part failure exceeds .13 hour.