Question :
| Literacy rate (in %) | 45 – 55 | 55 – 65 | 65 – 75 | 75 – 85 | 85 – 95 |
| Number of cities | 3 | 10 | 11 | 8 | 3 |
Solution :
Let the assumed mean, A = 70 and class size, h = 10
So, \(u_i\) = \(x_i – 70\over 10\)
Literacy rate (in %)
Mid-value (\(x_i\))
Frequency (\(f_i\))
\(u_i\) = \(x_i – 70\over 10\)
\(f_iu_i\)
45 – 55
50
3
-2
-6
55 – 65
60
10
-1
-10
65 – 75
70
11
0
0
75 – 85
80
8
1
8
85 – 95
90
3
2
6
Total
35
-2
Mean = A + h \(\times\) \(\sum f_iu_i\over \sum f_i\)
= 70 + 10 \(\times\) \(-2\over 35\) = 70 – 0.57 = 69.43%
Thus, mean literacy rate is 69.43%