Adding one unusually high sale to a data set will have what effect?
Correct Answer
A) It moves the mean and leaves the median unchanged
Why this is correct: The mean (average) is calculated using all values, so an extreme high sale pulls the mean upward. The median (middle value) is based on position in an ordered list; adding one high value may shift the median slightly if it changes the middle position, but often it remains unchanged, especially in larger data sets. Why the other choices are wrong: "It moves the median and leaves the mean unchanged" reverses the effect. "It moves both measures by the same dollar amount" is false; each measure reacts differently. "It leaves both measures completely unaffected" ignores the mean's sensitivity to all values. Exam tip: Mean is sensitive to outliers; median is resistant. This is a key distinction in data analysis.
Why This Is the Correct Answer
Why this is correct: The mean (average) is calculated using all values, so an extreme high sale pulls the mean upward. The median (middle value) is based on position in an ordered list; adding one high value may shift the median slightly if it changes the middle position, but often it remains unchanged, especially in larger data sets. Why the other choices are wrong: "It moves the median and leaves the mean unchanged" reverses the effect. "It moves both measures by the same dollar amount" is false; each measure reacts differently. "It leaves both measures completely unaffected" ignores the mean's sensitivity to all values. Exam tip: Mean is sensitive to outliers; median is resistant. This is a key distinction in data analysis.
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