Mathematics
Find the mean (correct to one place of decimal) by using short-cut method.
| x | f |
|---|---|
| 40 | 14 |
| 41 | 28 |
| 43 | 38 |
| 45 | 50 |
| 46 | 40 |
| 49 | 20 |
| 50 | 10 |
Measures of Central Tendency
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Answer
Let the assumed mean (A) be 45
| x | f | d = x - A | fd |
|---|---|---|---|
| 40 | 14 | 40 - 45 = -5 | -70 |
| 41 | 28 | 41 - 45 = -4 | -112 |
| 43 | 38 | 43 - 45 = -2 | -76 |
| A = 45 | 50 | 45 - 45 = 0 | 0 |
| 46 | 40 | 46 - 45 = 1 | 40 |
| 49 | 20 | 49 - 45 = 4 | 80 |
| 50 | 10 | 50 - 45 = 5 | 50 |
| Total | Σf = 200 | Σfd = -88 |
By formula,
Mean = A +
= 45 - 0.44
= 44.56 ≈ 44.6
Hence, mean = 44.6
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