An anomalous result is one that does not fit the pattern of the others. In repeats of 31, 30 and 45 s, the 45 s is anomalous. It might come from a mistake: starting the stopwatch late, misreading a scale, or not keeping a control variable the same.
Scientists look for anomalies in tables and on graphs, where an anomalous point lies far from the line. They try to explain them and, if possible, repeat that measurement. An anomalous result should not be included when calculating the mean, because it would pull the mean away from the true value.
Worked example
Repeats are 18, 19 and 30 cm. Which is anomalous, and what is the mean of the others?
- 18 and 19 are close; 30 is far away.
- 30 cm is anomalous.
Answer:Mean of the others = (18 + 19) ÷ 2 = 18.5 cm.
Key words
- anomalous
- does not fit the pattern
- error
- a mistake or problem in measuring
- outlier
- another word for an anomalous point
- repeat
- measure again to check
Practise this
New questions every time.