What is the simplest criterion of rejection for Dixon's Range Statistic?

• A. D/R > 0.3
• B. D/R < 0.3
• C. D/R = 1
• D. R/D > 0.3

Answer: (A)

Dixon's Range Statistic uses a simple distance ratio to decide whether an extreme value should be considered an outlier. You take D as the gap between the suspected extreme value and its nearest neighbor, and R as the overall spread of the data (the difference between the maximum and minimum). The easiest rejection rule is to look at the ratio D divided by R. If this ratio is greater than 0.3, the extreme value is considered an outlier and is rejected. This on-the-spot criterion gives a quick decision in small samples, though the formal test uses critical values that depend on sample size and the chosen significance level. If D/R is not above 0.3, the data point isn’t rejected by this simple rule.