Question

Question 13 D 1 pts A university of dean of students wishes to estimate the average number of hours students spend doing homework per week. The standard deviation from a previous study is 6.2 hours. How large a sample must be selected if he wants to be 99% confident of finding whether the true mean differs from the sample mean by 1.5 hours? 1 pts Question 14 If the variance of a national accounting examination is 900, how large a sample is needed to estimate the true mean score within 5 points with 99% confidence?

Answer 1

Answer: 13) the maximum error is given as 1.5 hours and the standard deviation is 6.2hours. 5= 6.2 E=1.5 of value a is Now, for aqt of confidence level C1-0.99) or 0.01 42 -0,07 -0.005 or.o.5-12 20.4950 thos, from the table, we get that the value of 2/2 is 2.58 Hence, the sample size n can be found as: 60). - (05380) n = 11 3-7209) Approxmatly. so, the ple size need to be at least (114)