> e 0 e Bachieve.macmillanlearning.com 6 [1] + 33 m Achieve: Sign up Instructions - MATH 2830 P1 206 a Assessment | (reduction to Statistics Spring 2022-206 - Achieve a Crunchlt EE 2 of 5 Questions 1 Question 0 of no Attempts 2 Question 0 of w Attempm 3 Question 0 of no Attempts 4 Question 0 0t 06 Attempts 5 Question 0 of no Attempts 0% 0% 0% 0% 0% ( Question 2 of 5 > A research rm supplies manufacturers with estimates of the sales of their products from samples of stores. Marketing managers often look at the sales estimates and ignore sampling error. An SRS of 50 stores this month shows mean sales of 41 units of a particular appliance with a standard deviation of 11 units. During the same month last year, an SRS of 52 stores gave mean sales of 38 units of the same appliances with a standard deviation of 13 units. An increase from 38 to 41 is a rise of 7.9% . The marketing manager is happy because sales are up 7.9%. (a) Give a 95% condence interval for the difference in mean number of units of the appliance sold at all retail stores. (Enter your answer rounded to three decimal places.) (b) Explain in language that the manager can understand why he cannot be condent that sales rose by 7.9% and, in fact, may have dropped. Select the best explanation from the choices. O The 95% condence interval does not contain zero. This means it is possible that there is not a signicant difference in the mean number of units sold from this year to last year. In fact, because the intervals contain negative numbers, it is possible that the mean number of units sold last year was greater than the mean number of units sold this year. Question Source: Moore, The Basic Practice Of Statistics, 8e | Publisher: W.H. Freeman A 'mm \"Mina..- \"mm...\" :. "MW\". cal\" "M .I..l:..:mi., .... nan. m...\