Let the assumed mean (A) = 3
No. of students absent (xi) |
No. of days (fi) |
ui = xi - A = xi - 3 |
fiui |
0 |
1 |
-3 |
-3 |
1 |
4 |
-2 |
-8 |
2 |
10 |
-1 |
-8 |
3 |
50 |
0 |
0 |
4 |
34 |
1 |
34 |
5 |
15 |
2 |
30 |
6 |
4 |
3 |
12 |
7 |
2 |
4 |
8 |
|
N = 120 |
|
\(\sum\)fiui = 63 |
Mean number of students absent per day = A + \(\frac{\sum f_iu_i}{N}\)
\(=3+\frac{63}{120}=\frac{360+63}{120}\)
\(=3.53\) (approx)