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Question 1 In the last quarter, the advertising expenditure of a random sample of companies of City A are listed in the following table: Quarterly advertising Number of companies expenditure ($'000) 25 to less than 35 5 35 to less than 45 10 45 to less than 55 21 55 to less than 65 16 65 to less than 75 8 (a) Calculate the mean, median and standard deviation. [9 marks] (b) Estimate, from the frequency distribution, the probability of a randomly selected company of City A with quarterly advertising expenditure at least $48,000. [3 marks] (c) Construct a 95% condence interval for the mean quarterly advertising expenditure in the last quarter among all companies of City A. Interpret your results. [8 marks]