Voltage sags and swells. Refer to the Electrical Engineering (Vol. 95, 2013) study of the power quality (sags and swells) of a transformer, Exercise 2.127 (p. 110). For transformers built for heavy industry, the distribution of the number of sags per week has a mean of 353 with a standard deviation of 30. Of interest is x, the sample mean number of sags per week for a random sample of 45 transformers. a. Find E1x2 and interpret its value. b. Find Var1x2. 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 400