Use the step-deviation method to find the arithmetic mean from the following data.
X | 18 | 19 | 20 | 21 | 22 | 23 | 24 |
F | 170 | 320 | 530 | 700 | 230 | 140 | 110 |
Let the assumed mean be A = 21
= h = x2 – x1 = 19 – 18 = 1
Thus, we prepare the table given below:
|
|
|
|
18 | 170 | -3 | -510 |
19 | 320 | -2 | -640 |
20 | 530 | -1 | -330 |
21 | 700 | 0 | 0 |
22 | 230 | 1 | 230 |
23 | 140 | 2 | 280 |
24 | 110 | 3 | 330 |
∑ |
|
We Know that,
Mean =
Hence, The Mean value of given distribution = 20.62.
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