6 Find the mean and standard deviation using short-cut method.
60 | 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | |
2 | 1 | 12 | 29 | 25 | 12 | 10 | 4 | 5 |
Let the assumed mean, A = 64 and h = 1
60 | 2 | -4 | 16 | -8 | 32 |
61 | 1 | -3 | 9 | -3 | 9 |
62 | 12 | -2 | 4 | -24 | 48 |
63 | 29 | -1 | 1 | -29 | 29 |
64 | 25 | 0 | 0 | 0 | 0 |
65 | 12 | 1 | 1 | 12 | 12 |
66 | 10 | 2 | 4 | 20 | 40 |
67 | 4 | 3 | 9 | 12 | 36 |
68 | 5 | 4 | 16 | 20 | 80 |
=100 |
|
= 0 |
=286 |
Mean,
We know, Variance,
We know, Standard Deviation =
Hence, Mean = 64 and Standard Deviation = 1.691