1. The number of hours worked (per week) by 400 statistic dents are shown below Number of hours Frequency 0 to 9 20 10 to 19 80 20 to 29 200 30 to 39 100 Calculate the group mean The following data set shows the total time employees to pass the whmis on-lining. The 25th percentile equals 62. Determine tje 75th percentile. 51 55 56 59 62 62 63 65 66 70 71 72 73 79 79 80 85 90 94 98