The highest mark in a class of 11 was entered as 59 instead of 95. Even as 59 it was still the highest mark, and it was the only 59. The most common mark in the class was 48, scored by three students. Which measures change when the mark is corrected?

Only the mean changesCorrect answerYour answerThe mean and the range change; the median and the mode do notCorrect answerYour answerThe mean, the median and the range all changeCorrect answerYour answerOnly the range changesCorrect answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer B

Correct answer: B

Raising the top value keeps every mark in the same position, so the median (6th value) stays put.
The mode depends on repeated values; 59 appeared once, so the mode is unaffected.
The total rises by 36, so the mean rises by $36 \div 11$ , and the range rises by 36.

Worth noting

Changing an extreme value moves the mean and the range, but not the median or the mode, as long as the order of the middle values is untouched.

Concept: Which measures react to a change in an extreme value
Typical timeTypical: 70 s
Your timeYours: —

The rule this testsWhen values change

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Ten questions from Mean, Median and Mode, at your own pace.

The highest mark in a class of 11 was entered as 59 instead of 95. Even as 59 it was still the highest mark, and it was the only 59. The most common mark in the class was 48, scored by three students. Which measures change when the mark is corrected?

Explanation