4. The long-distance calls made by employees of a company are normally distributed with a mean of 6.3 minutes and a standard deviation of 2.2 minutes. Answer the following questions. a) What is the probability that a call lasts less than 4 minutes? b) How long do the longest 10% of calls last? (Determine the cutoff point to the longest 10% of calls). Round up your answer to 2 decimal places