LLD Records is a store that specializes in old-fashioned vinyl records. Some of the store's market research of college students is done during promotions on college campuses, while other market research of college students is done through email, phone, website, and in-store questionnaires. In all cases, for each vinyl record, the company solicits an "intent-to-purchase" score from the student, with 1 being the lowest score ("no intent to purchase") and 100 being the highest score ("full intent to purchase"). The store manager finds the following information for 120 intent-to-purchase scores for a newly acquired vinyl record: Group Sample Sample Sample size mean variance On campus 24 65.8 110.3 By email 24 71.5 83.1 By phone 24 61.9 123.2 On the 24 66.3 99.0 website In the store 24 66.3 84.0 Send data to calculator Send data to Excel Suppose that the five populations of scores from which these samples were drawn are approximately normally distributed and have the same mean and the same variance. Answer the following, carrying your intermediate computations to at least three decimal places and rounding your responses to at least one decimal place. (a) Give an estimate of this common population variance by pooling the sample variances given. (b) Give an estimate of this common population variance based on the variance of the sample means given. 10