statistical significance (redirected from significance level)

statistical significance,

n a difference of such magnitude between two statistics, computed from separate samples, that the probability of the value obtained will not occur by chance alone with significant frequency and hence can be attributed to something other than chance. In modern investigation the generally accepted value for significance must have a probability of occurrence by chance factors equal to or less than five times in 100 (
p < 0.05). Other significance levels commonly used are as follows: less than one chance in 100 (
p > 0.01), less than five chances in 1000 (
p < 0.005), and less than one chance in 1000 (
p < 0.001).

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statistical significance Significance Statistics A statement of the probability that an observation represents a true causal relationship and not a chance occurrence; the probability that an event or difference occurred as the result of an intervention–eg, a vaccine, rather than by chance alone; this probability is determined by using statistical tests to evaluate collected data. See Significance.