Diabetics need to keep close watch on glucose blood levels (mg/100 ml). The 12-hour fasting blood glucose levels for twenty-five diabetics are given below. If you use six classes for a frequency distribution of these values, what is the class width?
133 71 152 118 148 155 125 112 108 98 89 151 193 65 98 105 128 50 173 148 41 58 173 48 107