Mathematics
The following table gives the heights of plants in centimeter. If the mean height of plants is 60.95 cm; find the value of 'f'.
| Height (cm) | No. of plants |
|---|---|
| 50 | 2 |
| 55 | 4 |
| 58 | 10 |
| 60 | f |
| 65 | 5 |
| 70 | 4 |
| 71 | 3 |
Measures of Central Tendency
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Answer
| Height (x) | No. of plants (f) | fx |
|---|---|---|
| 50 | 2 | 100 |
| 55 | 4 | 220 |
| 58 | 10 | 580 |
| 60 | f | 60f |
| 65 | 5 | 325 |
| 70 | 4 | 280 |
| 71 | 3 | 213 |
| Total | Σf = 28 + f | Σfx = 1718 + 60f |
We know that,
n = Σf = 28 + f
By formula,
⇒ Mean =
⇒ 60.95 =
⇒ 60.95(28 + f) = 1718 + 60f
⇒ 1706.6 + 60.95f = 1718 + 60f
⇒ 60.95f - 60f = 1718 - 1706.6
⇒ 0.95f = 11.4
⇒ f = = 12.
Hence, f = 12.
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