A study examined transformer voltage sags and swells. For a sample of 106 transformers built for heavy industry, the mean number of sags per week was 40 and the mean number of swells per week was 182. Assume the standard deviation of the sag distribution is 30 sags per week and the standard deviation of the swell distribution is 20 swells per week. Suppose one of the transformers is randomly selected and found to have 399 sags and 118 swells in a week. a. Find the z-score for the number of sags for this transformer. Interpret this value. b. Find the z-score for the number of swells for this transformer. Interpret this value. a. z= (Round to two decimal places as needed.)