Arithmetic Mean

In this lesson we will discuss the most common single measure of central tendency, the arithmetic mean, often called the average.Suppose you just purchased your first car, and you are wondering what kind of gas mileage it gets. If you collect the data in the table below from your first 4 tanks of gas, how could you calculate your average gas mileage? Is the mean gas mileage different if it is calculated as the average of the mileages from each tank instead of calculated using the total miles and total gallons?

Grades 6 through 7 Material from CK-12

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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.




Use measures of center and measures of variability for numerical data from random samples to draw informal comparative inferences about two populations.



Informally assess the degree of visual overlap of two numerical data distributions with similar variabilities, measuring the difference between the centers by expressing it as a multiple of a measure of variability.