2. Two mechanics are being compared by a potential customer. The time to complete an oil change at each location on a Thursday is listed for one day. Mechanics A+ #1 Mechanics Time (minutes) Frequency Time (minutes) Frequency 0 - 10 0 0 - 10 1 10 - 20 10 10 - 20 1 20 - 30 7 20 - 30 6 30 - 40 12 30 - 40 18 40 - 50 3 40 - 50 20 50 - 60 5 50 - 60 4 f. Suppose choosing the midpoints of each interval isn't accurate. We should choose the maximum of each. So, the category from 0 - 10 min would not be 5 min in our calculation, but 10 min. Will this affect the standard deviation or the IQR more? keep in mind... the mean of 31.22 and standard deviation of 14.23 for mechanics A+ and mean of 38.4 and standard deviation of 9.92 of #1 mechanics