GROUPED FREQUENCY DISTRIBUTION EXAMPLE

The blood glucose level, in milligrams per deciliter, for 60 patients is shown below. Construct a frequency distribution for the data set, using six classes.

55 115 118 114 59 109 63 97 90 59 105 81 84 81 82 61 103 77 82 76 68 86 97 80 77 85 69 62 101 83 58 83 101 86 84 78 59 92 88 97 87 92 70 86 72 84 82 84 101 80 93 56 65 91 75 78 100 74 74 90

Step 1: H = 118 L = 55

Step 2: R = 118 - 55 = 63

Step 3: Number of classes, say, 6.

Step 4: 63/6 = 10.5 or about 11

Step 5: Find lower limits, 55, 66, 77, 88, 99, 110

Steps 6 - 10

Class Limits Class Boundaries f Percent cf cf%

55 – 65 54.5 -65.5 10 16.6 10 16.6 66 - 76 65.5 -76.5 8 13.3 18 29.9 77 - 87 76.5 - 87.5 22 36.7 40 66.6 88 - 98 87.5 - 98.5 10 16.6 50 83.2 99 - 109 98.5 - 109.5 7 11.7 57 94.9 110 - 120 109.5 - 120.5 3 5.0 60 99.9