Question

< webwork / stab22119 / homework6 / 4 Homework6: Problem 4 Previous Problem List Next (a) The director of an alumni association for a university wants to look at the relationship between the number of years since graduation and the amount of monetary contribution an alumnus makes to the university. He collects data on 50 alumni who have made contributions this year. The number of years since graduation has a mean of 5, and the amount of contribution has a mean of 224 dollars. Based on the least squares regression line fitted to the data, it is found that for every year increase since graduation, the contribution is expected to drop by 21 dollars. Predict the amount of contribution made by an alumnus who graduated 6 years ago. Do not found in intermediate steps. The predicted contribution of an alumnus who graduated 6 years ago is: in dollars, rounded to one decimal place) (by An analyst working for a telecommunications company has been asked to gauge the stress on its cellular networks due to the increasing use of smartphones. She decides to first look at the relationship between the number of minutes customers spent talking on their phones and the amount of cellular data they use. She collects a month's worth of data on 300 customers who have smartphones with data plans. The mean monthly cal time was found to be 241 minutes, and the mean amount of data consumed was found to be 496 megabytes. Based on the least squares regression inefitted to the data. It is found that for every minute increase in calling time. the data usage is expected to increase by 2.4 megabytes Predict the amount of data used by a customer who spends 369 minutes on the phone. Do not found in intermediate steps in megabytes, The predicted the amount of data used by a customer who spends 369 minutes on the phone is rounded to one decimal place

Answer 1

saluhion: (a) contribusiom at an Here we have alumnus who to find the predicted graduated 6 years ago Equation , -21 would be the slope at In the regressiam Equation, S.C., y = -21x4c Two ting "ct value subsiduting x, y values in y=-2184C 1.e., 224 = (-21) (5) + c where y = the contribution 143. bohon in in dollars S A dollars xz the no.al years since graduation 224 = (-21) (5)+C 224 = -los+c C = 224 tlos C = 329 regression Hence, the equation given by: y = 329 -21% Now, the prediched contribution at an alumnus who graduates

6 years ago isi 9 = 329-21(6) 2.329-126 y $203] Here we have to find the predicted amount as data used by a customer who spends 369 minutes on the phone: Data usage a mean(data consumed) - 2.4 (mean (Call dime) + 2.4 (calling 1 time) from the given data we have hassas & Data usage = 496-12.4(241)) +(2,4 (367) = 496- 518.4 +88516 -82.4 +88526 - 8032