At LLD Records, some of the market research of college students is done during promotions on college campuses, while other market research of college students is done through anonymous mail, phone, internet, and record store questionnaires. In all cases, the company solicits an "intent-to-purchase" score from the student, with 0 being the lowest score ("no intent to purchase") and 100 being the highest score ("full intent to purchase"). The manager finds the following information for 150 intent-to-purchase scores for a soon-to-be-released CD: Sample Sample Sample size Group mean variance On campus 30 64.5 68.9 By mail 30 63.0 77.1 By phone 30 62.8 125.1 By internet 30 62.3 106.0 In a store 30 68.2 85.9 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 based on the variance of the sample means given. |(b) Give an estimate of this common population variance by pooling the sample variances given.
At LLD Records, some of the market research of college students is done during promotions on college campuses, while other market research of college students is done through anonymous mail, phone, internet, and record store questionnaires. In all cases, the company solicits an "intent-to-purchase" score from the student, with 0 being the lowest score ("no intent to purchase") and 100 being the highest score ("full intent to purchase"). The manager finds the following information for 150 intent-to-purchase scores for a soon-to-be-released CD: Sample Sample Sample size Group mean variance On campus 30 64.5 68.9 By mail 30 63.0 77.1 By phone 30 62.8 125.1 By internet 30 62.3 106.0 In a store 30 68.2 85.9 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 based on the variance of the sample means given. |(b) Give an estimate of this common population variance by pooling the sample variances given.
Holt Mcdougal Larson Pre-algebra: Student Edition 2012
1st Edition
ISBN:9780547587776
Author:HOLT MCDOUGAL
Publisher:HOLT MCDOUGAL
Chapter11: Data Analysis And Probability
Section: Chapter Questions
Problem 8CR
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