1: Table 1 shows the number of customers visited by a salesman over an 80-week period. Table 1: Customers Visited Over an 80-Week Period 68 64 75 82 68 60 62 88 76 93 73 79 88 73 60 93 71 59 85 75 61 65 75 87 74 62 95 78 63 72 66 78 82 75 94 77 69 74 68 60 96 78 89 61 75 95 60 79 83 71 79 62 67 97 78 85 76 65 71 75 65 80 73 57 88 78 62 76 53 74 86 67 73 81 72 63 76 75 85 77 Using data from this table do the following: a) Determine the mean, mode(s) and median. b) Determine the values for the first and third quartiles (Q1 and Q3). c) Calculate the interquartile range and semi interquartile range. d) Calculate the variance and standard deviation. e) Form a grouped frequency table beginning from 50-54 (using 5 as the class interval). f) Create a suitable histogram to represent the number of customers. g) Create a frequency polygon for the data