Question

Problem C: Many smartwatches allow individuals to track their fitness. In a study, a user recorded the number of steps (2) taken per day versus the calories (y) burned during this activity. Over a period of 7 days, the user generated the following summary information: n=7, ti = 29500, y = 1328, tiyi = 5732550, Sz = 715.2, and sy = 32.2. (13) Refer to Problem C. Calculate the correlation coefficient r for this dataset. (1) -0.984 (2) 0.984 (3) -0.566 (4) 0.566 (14) Refer to Problem C. Calculate the slope of the least-squares regression line for this dataset. (1) 0.044 (2) -0.044 (3) 2.3 (4) -2.3 (15) Refer to Problem C. If the person took 4000 steps on a particular day, how many calories would you predict the person to burn? (1) About 100. (2) About 2000. (3) About 50. (4) About 180.

Answer 1

AAS Given : net Zxi = 29500 EY; = 1328 Ex4 = 5732 55 Sc= 715.2 sy = 32.2 Sample covariance Sy Colx.41 = EX: 74 h [ 5432 650 - 29500x 1325 구 Coursy Sag 22663.095 sxY J o CON(xY1 sx sy 02 Syasy = 22663.0gs 715 2 x 32.2 0.98 4 (2). 2] Let y = dit Bxt & be regression ean .: slopez B cov (X.

= 22 663 035 715.22 0.0443 0044 1 / 84 - f t Evi 1328 0.044x 29500 7 7 4.286 Regression line is y = 6.286 + 0-0448 * = 4000 when 9= 4:286 + 0-0 44x4000 180.2857 Ahs about 180