The weekly observations on cost of living index in a certain city for the year 2004-2005 are given below. Compute the weekly cost of living index.
Cost of living Cost of living | Number of Students | Cost of living Index | Number of students |
1400-1500 | 3 | 1700-1800 | 9 |
1500-1600 | 10 | 1800-1900 | 6 |
1600-1700 | 20 | 1900-2000 | 2 |
Let the assumed mean (A) = 1650
Class interval | Mid value (xi) | di = xi – A = xi – 1650 | ui = | Frequency (fi) | fiui |
1400-1500 | 1450 | -200 | -2 | 3 | -10 |
1500-1600 | 1550 | -100 | -1 | 10 | -10 |
1600-1700 | 1650 | 0 | 0 | 20 | 0 |
1700-1800 | 1750 | 100 | 1 | 9 | 9 |
1800-1900 | 1850 | 200 | 2 | 6 | 12 |
1900-2000 | 1950 | 300 | 3 | 2 | 6 |
N = 52 | ∑fiui = 7 |
We have, A = 1650
h = 100
Mean = A + h * 
= 1650 + 100 * 
= 1650 + 
= 
= 
= 1663.46
16