Suggested answer to exercise: Height from the 2005 questionnaire, part 2, 2

Question 2: What would you estimate the standard deviation of height to be?

Suggested answer

The range should be just a bit more than four standard deviations. If the range goes from the middle of the leftmost bar to the middle of the rightmost bar, this would be 147.5 to 182.5 cm, or 182.5 - 147.5 = 35 cm. Thus four standard deviations would be about 30 cm, givng an estimated standard deviation = 30/4 = 7.5 cm.

In fact, the standard deviation for this sample is 6.8 cm, a little less than my estimate.

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Last updated: 10 October, 2006.

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