12. Calculate the mean deviation about median age for the age distribution of persons given below:
Age (in years) | ||||||||
Number |
[Hint Convert the given data into continuous frequency distribution by subtracting from the lower limit and adding to the upper limit of each class interval]
Age (in years) |
Number
|
Cumulative Frequency c.f. |
Mid Points |
||
15.5-20.5 | 5 | 5 | 18 | 20 | 100 |
20.5-25.5 | 6 | 11 | 23 | 15 | 90 |
25.5-30.5 | 12 | 23 | 28 | 10 | 120 |
30.5-35.5 | 14 | 37 | 33 | 5 | 70 |
35.5-40.5 | 26 | 63 | 38 | 0 | 0 |
40.5-45.5 | 12 | 75 | 43 | 5 | 60 |
45.5-50.5 | 16 | 91 | 48 | 10 | 160 |
50.5-55.5 | 9 | 100 | 53 | 15 | 135 |
|
|
=735 |
Now, N = 100, which is even.
The class interval containing or item is 35.5-40.5. Therefore, 35.5-40.5 is the median class.
We know,
Median
Here, l = 35.5, C = 37, f = 26, h = 5 and N = 100
Therefore, Median
Now, we calculate the absolute values of the deviations from median, and
= 735
Hence, the mean deviation about the median is 7.35