1. Mean of Grouped Data
OCR Stage 6

2. Mean of Discrete data Mean = 49 ÷ 25 = 1.96 children per house 6 1 4 2
Number of children, c
Frequency
[no of houses]
C x frequency 6 1 4 2 5 3 7
Totals
0 x 6 = 0
1 x 4 = 4
2 x 5 = 10
3 x 7 = 21
4 x 1 = 4
Total Number of Houses
Total Number of Children
5 x 2 = 10 25 49

3. Mean of Continuous data
Mean = ÷ 65 = 171.3cm
Height of the AVERAGE person
Height, h
[cm]
Frequency
Midpoints
midpoint x frequency
155 ≤ h < 160 2
160 ≤ h < 165 6
165 ≤ h < 170 18
170 ≤ h < 175 25
175 ≤ h < 180 9
180 ≤ h < 185 4
185 ≤ h < 190 1
Totals
157.5
157.5 x 2 = 315
162.5
162.5 x 6 = 975
167.5
167.5 x 18 = 3015
172.5
172.5 x 25 =
177.5
177.5 x 9 =
182.5
182.5 x 4 = 730
187.5
187.5 x 1 = 65
Total number of people
Total of their Heights