4. (8 po The Boston Security Analyst Society, Inc. (BSAS) is a nonprofit association that serves as a forum for the exchange of ideas for the investment community. Suppose the ages of its members are based on the following frequency distribution: Frequency Midpoint (m) m.fi Age From 18 to 25 5 From 25 to 35 14 From 35 to 45 42 42 From 45 to 55 29 From 55 to 65 23 From 60 to 90 17 (m-x). fi (note: fill in the table correctly and completely to receive full credit) a) Use the summarized data to find out the average age of members (2nd decimal place). b) What is the sample variance and standard deviation of member's age (2nd decimal