4

A pediatrician has obtained the following table which represents the number of children who begin to walk for the first time at different ages:

Months Children
9 1
10 4
11 9
12 16
13 11
14 8
15 1

1. Draw the respective frequency polygon.

2. Calculate the mode, median, mean and variance.


Frequency Polygon

Frequency Polygon


xi fi Ni xi · fi i · fi
9 1 1 9 81
10 4 5 40 400
11 9 14 99 1089
12 16 30 192 2304
13 11 41 143 1859
14 8 49 112 1568
15 1 50 15 225
  50   610 7526

Mode

Mo = 12

Median

50/2 = 25 Me = 12

Arithmetic Mean

Arithmetic Mean Solution

Variance

Variance Solution