Q26 of 46 Page 278

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

Given the lives (in hours) of 5 bulbs is 1357, 1090, 1666, 1494, 1623

Here mean,


This can be written in table form as,



Hence Mean Deviation becomes,



Therefore, the mean deviation about the mean of the lives of 5 bulbs is 178

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