Question -
Answer -
| Literacy rate (in %) | 45-55 | 55-65 | 65-75 | 75-85 | 85-98 |
| Number of cities | 3 | 10 | 11 | 8 | 3 |
Solution:
Find the midpoint of the given interval usingthe formula.
Midpoint (xi) = (upper limit +lower limit)/2
In this case, the value of mid-point (xi)is very large, so let us assume the mean value, A = 70 and class interval is h= 10.
So, ui = (xi-A)/h =ui = (xi-70)/10
Substitute and find the values as follows:
| Class Interval | Frequency (fi) | (xi) | di = xi – a | ui = di/h | fiui |
| 45-55 | 3 | 50 | -20 | -2 | -6 |
| 55-65 | 10 | 60 | -10 | -1 | -10 |
| 65-75 | 11 | 70 | 0 | 0 | 0 |
| 75-85 | 8 | 80 | 10 | 1 | 8 |
| 85-95 | 3 | 90 | 20 | 2 | 6 |
| Sum fi = 35 | | | | Sum fiui = -2 |
So, Mean = x̄ = A+(∑fiui /∑fi)×h
= 70+(-2/35)×10
= 69.42
Therefore, the mean literacy part = 69.42