4. A researcher is conducting a Tracer Study on the alumni of a certain university 5 years after graduation. He determines the monthly income of the 100 respondents and are presented in a distribution as shown below. Classes 13,000-13,999 8 14,000-14,999 20 15,000-15,999 16 16,000-16,999 23 17.000-17,999 10 18,000-18,999 12 19,000-19,999 5 20,000-20,999 6 a. Compute and interpret the value of Q, and the average income. b. Show the histogram of the data