Question
Find the mean of the following frequency distribution using assumed mean method
| Classes | 2-8 | 8-14 | 14-20 | 20-26 | 26-32 |
| Frequency f: | 6 | 3 | 12 | 11 | 8 |
✓
Answer
Construct the following table:
Here, $A =17$
Mean $=A+\frac{\sum f_i d_i}{\sum f_i}$
$\sum f_i d_i=72$ and $\sum f=40$
Mean $=17+\frac{72}{40}$
Mean $=17+1.8=18.8$
Hence, the mean is 18.8 .
| Classes | Fi | Xi | di = xi - A | di × fi |
| 2-8 | 6 | 5 | -12 | -72 |
| 8-14 | 3 | 11 | -6 | -18 |
| 14-20 | 12 | 17 = A | $0$ | 0 |
| 20-26 | 11 | 23 | 6 | 66 |
| 26-32 | 8 | 29 | 12 | 96 |
Here, $A =17$
Mean $=A+\frac{\sum f_i d_i}{\sum f_i}$
$\sum f_i d_i=72$ and $\sum f=40$
Mean $=17+\frac{72}{40}$
Mean $=17+1.8=18.8$
Hence, the mean is 18.8 .
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