Given the heights below, find mean heights using coding method
| Heights (In inches) |
Class marks (x) |
Frequency(f) |
| 60-62 |
61 |
5 |
| 63-65 |
64 |
18 |
| 66-68 |
67 |
42 |
| 69-71 |
70 |
27 |
| 72-74 |
73 |
8 |
solution
The tabke can be arranged as below
| x |
u |
f |
f*u |
| 61 |
-2 |
5 |
-10 |
| 64 |
-1 |
18 |
-18 |
| 67=a |
0 |
42 |
0 |
| 70 |
1 |
27 |
27 |
| 73 |
2 |
8 |
16 |
|
n=100 |
\[\sum_{n=1}^{5}f=100\] |
\[\sum_{n=1}^{5}fu=100\]=15 |
Mean using coding theorem \[ \widetilde{X}\]=\[a+\frac{Y}{X}*c\] where c is class interval
=\[ 67+\frac{15}{100}*3=67.45\]
