Mathematics
The following table gives the ages of 50 students of a class. Find the arithmetic mean of their ages.
| Age (years) | No. of students |
|---|---|
| 16 - 18 | 2 |
| 18 - 20 | 7 |
| 20 - 22 | 21 |
| 22 - 24 | 17 |
| 24 - 26 | 3 |
Related Questions
If the mean of the data given in adjoining table is 20, the relation between x1 and x2 is :
x f fx 10 x1 20 20 30 x2 x1 + x2 = 30
x1 - x2 = 15
x1 - x2 = 0
x1 + x2 = 20
The mean of data, represented by given diagram is :
53
47
42
51
The following are the marks obtained by 70 boys in a class test.
Marks No. of boys 30 - 40 10 40 - 50 12 50 - 60 14 60 - 70 12 70 - 80 9 80 - 90 7 90 - 100 6 Calculate the mean by :
(i) Short-cut method
(ii) Step-deviation method
Find mean by 'step-deviation method' :
C.I. Frequency 63 - 70 9 70 - 77 13 77 - 84 27 84 - 91 38 91 - 98 32 98 - 105 16 105 - 112 15