According to a study of the power quality (sags and swells) of a transformer, for transformers built for heavy industry, the
distribution of the number of sags per week has a mean of 360 with a standard deviation of 108. Of interest is x overbar, the sample mean number of sags per week for a random sample of 216 transformers. Complete parts a through d below. a. Find E (x)
b. Find Var(x)
c. Describe the shape of the sampling distribution of x
d. How likely is it to observe a sample mean number of sags per week that exceeds 414?
Given that according to a study of the power quality (sags and swells) of a transformer, for transformers built for heavy industry, the distribution of the number of sags per week has a mean of 360 with a standard deviation of 108
Sample size n =216
By central limit theorem we have sample mean will follow a normal distribution with mean=360 and std deviation =