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Question 4 The following is a sample of the planned expenditure on electronic mobile devices (cellphone, iPad, etc.) in the Not yet answered shopping season of 2020 from households in Bondi, NSW. Marked out of 4.00 Household ID IDO1 ID02 IDO3 ID04 ID05 ID06 ID07 ID08 ID09 ID10 ID11 ID12 Flag question Planned 6 3 4 4 5 3 8 4 2 5 5 5 expenditure (thousand dollars) For all the blanks below, please just input numerical answers, round the answers to 2 decimal places, and ignore the symbols of the dollar, percentage, comma etc. Also, note that the unit of the blanks are thousand, so you do not need to add "000" to your answer. Question (a) [1 mark] The point estimate of the mean expenditure is thousand dollars. Question (b) [1 mark] The sample standard deviation of the expenditure is thousand dollars. Question (c) [2 marks] The 95% confidence interval of the mean expenditure is from thousand do thousand dollars