The marks obtained by 80 students in a test are given below:
Marks | 4 | 12 | 20 | 28 | 36 | 44 |
Number of students | 8 | 10 | 16 | 24 | 15 | 7 |
Find the modal marks.
We can draw the table as below,
Marks (x) | Number of students (f) | Cumulative frequency | Fx |
4 | 8 | 8 | 32 |
12 | 10 | 18 | 120 |
20 | 16 | 36 | 320 |
28 | 24 | 60 | 672 |
36 | 15 | 75 | 540 |
44 | 7 | 80 | 308 |
N = 80 | ∑fx = 1992 |
We have;
N = 80 (even number)
Median =
Now,
∑fx = 1992 and ∑f = N = 80
Mean =
Hence,
Mode = 3(median) – 2 (mean)
= 3×28 - 2×24.9
= 84 –49.8
= 34.2