Calculate the value of mode from the following data by using the formula. Mode = 3 median - 2 mean:
marks 10 20 30 40 50 60 70 80 90
(less than)
no. of students 5 15 98 242 367 405 425 438 439.
Class interval | Frequency Fi |
Mid value Xi |
Cumulative frequency |
FiXi |
0-10 | 5 | 5 | 5 | 25 |
10-20 | 10 | 15 | 15 | 150 |
20-30 | 83 | 25 | 98 | 2075 |
30-40 | 144 | 35 | 242 | 5040 |
40-50 | 125 | 45 | 367 | 5625 |
50-60 | 38 | 55 | 405 | 2090 |
60-70 | 20 | 65 | 425 | 1300 |
70-80 | 13 | 75 | 438 | 975 |
80-90 | 1 | 85 | 439 | 85 |
=17365 |
Mean=
=
Median class is 40-50 as n/2 is 219.5
Median=
Mode=3Median-2 Mean
=3*38.43-2*39.56
=115.29-79.12
=36.17