Following information pertains to the daily income of 150 families. Calculate the arithmetic mean.
Income (in Rs)
Number of families
More than 75
150
More than 85
140
More than 95
115
More than 105
95
More than 115
70
More than 125
60
More than 135
40
More than 145
25
|
Income |
No. of families |
Frequency |
Mid Value |
fm |
|
Class Interval |
(CF) |
(f) |
(m) |
|
|
75 – 85 |
150 |
150 – 140 = 10 |
80 |
800 |
|
85 – 95 |
140 |
140 – 115 = 25 |
90 |
2250 |
|
95 – 105 |
115 |
115 – 95 = 20 |
100 |
2000 |
|
105 – 115 |
95 |
95 – 70 = 25 |
110 |
2750 |
|
115 – 125 |
70 |
70 – 60 = 10 |
120 |
1200 |
|
125 – 135 |
60 |
60 – 40 = 20 |
130 |
2600 |
|
135 – 145 |
40 |
40 – 25 = 15 |
140 |
2100 |
|
145 – 155 |
25 |
25 |
150 |
3750 |
|
Total |
|
|
|
|
= Rs 116.33