THE MEAN OF THE FOLLOWING DISTRIBUTION IS 132 AND THE SUM OF THE OBSERVATION IS 50. FIND THE MISSING FREQUENCIES f1 AND F2.
Class Interval | xi | Frequency(fi) | ui=(xi-140/40) | fiui |
0-40 | 20 | 4 | -3 | -12 |
40-80 | 60 | 7 | -2 | -14 |
80-120 | 100 | f1 | -1 | -f1 |
120-160 | 140 | 12 | 0 | 0 |
160-200 | 180 | f2 | 1 | f2 |
200-240 | 220 | 9 | 2 | 18 |
| 720 |
|
|
|
Sum of frequency = 32+f1+f2
Also sum of frequency = 50 (given)
Therefore,
32+f1+f2= 50
f1+ f2= 18…………………….(i)
Mean = 132 (Given)
