Question 1 Last year's annual prot (corrected to the nearest million dollars) of a random sample of small and medium size companies of industrial sector A is given below. Annual rot $rm'llion 5 24 38 23 7 3 (a) Calculate the mean, median and standard deviation of last year's annual prot. [8 marks] (b) Estimate, from the frequency distribution table, the proportion of companies having last year's annual prot between $7.5 million and $25 million. [4 marks] (c) It is known that a randomly selected small and median size company had annual prot for last year larger than $7.5 million. Estimate, from the frequency distribution table, the probability that this company had annual prot not more than $25 million. [4 marks] (d) Construct a 95% condence interval for the population mean annual prot of all small and medium size companies of industrial sector A for last year. [4 marks]