SAT and ACT math terms · SAT Math, ACT Math
Mean, median and mode
Mean, median and mode: Measures of center: the mean is the average, the median is the middle value, and the mode is the most frequent value.
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What it means
The mean is sensitive to outliers, while the median is resistant. Adding a very large value to a data set increases the mean more than the median. For a data set with an even number of values, the median is the average of the two middle values.
Questions often ask how the mean or median changes when a value is added, removed or changed.
Example
Data: 2, 3, 3, 5, 12. Mean = 25 / 5 = 5. Median = 3. Mode = 3. The outlier 12 pulls the mean above the median.
On the exam
The SAT tests center and spread in one-variable data questions, often with dot plots, histograms or tables.