anova 7. a large marketing firm uses many photocopying machines, several of each of four different models. during the last six months, the office manager has tabulated for each machine the average number of minutes per week that it is out of service due to repairs, resulting in the following data: model g: 56 61 68 42 82 model h: model k: 74 77 92 63 54 25 36 29 56 44 model m: 78 105 89 112 61 perform an analysis of variance to decide whether the difference among the means of the four samples can be attributed to chance.state the conclusion.