Recognize that a measure of center for a numerical data set summarizes all of its values with a single number, while a measure of variation describes how its values vary with a single number.


"I Can Calculate and Interpret the Mean, Median, Mode, and Range of a given Data Set."
"Explain the difference between measures of center and measures of spread."
"Determine which Measure of Center best Summarizes the Data Set."


  • Mean- finding the sum of a set of numbers in a data set and then dividing the sum by the amount of numbers in the data set.
    • Another word for mean is average


  • Median- the middle number in a data set when listed from least to greatest.
    • If there is an even set of numbers in the data set, you must find the mean of the two middle numbers. (after listing them from least to greatest)
    • If there is an odd set of numbers in the data set, the middle number (after you have listed them from least to greatest) is your median.


  • Mode- The number that occurs the most often or frequently in a data set.
    • You can have more than one mode.
    • You can have no mode.
      • This occurs if all the numbers in the data set appear the same number of times. There is NO MODE when this occurs.


  • Range- The span of numbers in your data set.
    • Find the range by subtracting the lowest number in the data set from the highest number.

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