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Question
When tested, the lives (in hours) of 5 bulbs were noted as follows: 1357, 1090, 1666, 1494, 1623
The mean deviations (in hours) from their mean is ______.
Options
178
179
220
356
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Solution
The mean deviations (in hours) from their mean is 178.
Explanation:
The lines of 5 bulbs are given by 1357, 1090, 1666, 1494, 1623
∴ Mean = `(1357 + 1090 + 1666 + 1494 + 1623)/5`
⇒ `barx = 7230/5` = 1446
| `x_i` | `d_i = |x_i - barx|` |
| 1357 | 89 |
| 1090 | 256 |
| 1666 | 220 |
| 1494 | 48 |
| 1623 | 177 |
| Total | `sumd_i` = 890 |
∴ M.. = `(sumd_i)/n`
= `890/5`
= 178
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