Question

Both sets of values have an average of 13. Is Set A's standard deviation smaller, larger, or about the same as Set B's? (Note: This question can be answered by knowing the concept of standard deviation, without actually computing the standard deviation).

Set A: 1 2 3 23 24 25

Set B: 8 10 12 14 16 18

Answer 1

Set A's standard deviation is larger than Set B's

Explanation:

Standard deviation is a measure of variation. One way to judge the value of standard deviation is by looking at the range of the data. In general, a dataset with a smaller range will have a smaller standard deviation.

The range of data Set A is 25-1 = 24.

The range of data Set B is 18-8 = 10.

Set A's range is larger, so we expect its standard deviation to be larger.

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The standard deviation is the root of the mean of the squares of the differences from the mean. In Set A, the differences are ±12, ±11, ±10. In Set B, the differences are ±5, ±3, ±1. We don't actually need to compute the RMS difference to see that it is larger for Set A.

Set A's standard deviation is larger than Set B's.