3. The data show the amounts (in thousands of dollars) of the contracts for so drinks in local school districts. Can it be concluded that there is a difference in the averages? Give a reason why the result would be of concern to a cafeteria manager. Pepsi Coca-Cola 46 120 80 500 100 59 420 285 57 Source: Local school disuids. 4. A dietitian wishes to see if a person's cholesterol level will change if the diet is supplemented by a certain mineral. Six subjects were pretested, and then they took the mineral supplement for a 6-week period. The results are shown in the table. (Cholesterol level is measured in milligran per deciliter.) Can it be concluded that the cholesterol level has been changed? Subject | l 2 3 4 s 6 Before (x.) | 2l0 235 203 190 172 244 After-(X9 | I90 170 210 188 173 228 In a comparison of the cleaning action of four detergents, 20 pieces of white cloth were rst soiled with India ink. The cloths were then washed under controlled conditions with 5 pieces washed by each of the detergents. Unfortunately three pieces of cloth were 'lost' in the course of the experiment. Whiteness readings. made on the l7 remaining pieces of cloth. are shown below. Detergent A B C D 77 74 73 76 81 66 78 85 61 53 57 77 76 69 64 69 63 Assuming all whiteness readings to be normally distributed with common variance, test the hypothesis of no difference between the four brands as regards mean whiteness readings after washing