+ 4. A census was conducted to get the total weekly incomes of families in Village A and B an
table below summarised the frequency distribution.
Income (RM)
Number of families
Number of families
in Village A
in Village B
60 to less than 100
5
10
100 to less than 120
45
120 to less than 140
48
25
140 to less than 180
37
41
180 to less than 240
12
34
Calculate the mean and standard deviation of weekly income in Village A and Village B