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4.) Final exam scores for a past statistics course is listed below. Assume that this sample size is from a normally distributed population. 59 71 65 59 90 55 61 73 59 99 83 60 87 64 48 67 40 55 Show your work necessary to solve 68 69 97 43 61 87 a.) Find a confidence interval around the mean. Determine a 95% level of confidence. b.) Find a 90% level of confidence around the population variance. c.) Find a 90% level of confidence around the population standard deviation