Correction: Understanding statistical terms: 1
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Our article *Understanding statistical terms: 1* (*DTB* 2009: 47: 22–24) stated that the standard deviation of a population is calculated by “a formula (see box) that involves subtracting the mean value (µ) from each data value (x); squaring each of these differences; summing all these squared differences…dividing this sum by (n-1) where n is the number of data values; and taking the square root of the answer.”The penultimate part of this sentence should have read “…dividing this sum by n, where n is the number of data values…”. The formula was correctly written in the box accompanying the text.