A time study was conducted in a factory with the help of two samples A and B consisting of 10 workers. The time taken by the workers in each case recorded. From the particulars given below state which of the samples is more variable and which takes less time on an average.

Question: A time study was conducted in a factory with the help of two samples A and B consisting of 10 workers. The time taken by the workers in each case recorded. From the particulars given below state which of the samples is more variable and which takes less time on an average.

Time taken in minutes.
Sample A 130 125 120 135 140 145 130 145 140 150
Sample B 132 146 137 145 130 125 138 140 143 144

Solution:

Let us calculate mean and standard deviation first by rearranging the data in ascending order.

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This shows that on an average workers from sample A takes less time.

This shows that on an average workers from sample A takes less time.

Since CVx > CVy, the sample ‘A’ is more variable, though as we have seen the workers of sample A takes less time.