8-32.
HOW CAN I MEASURE SPREAD?

One way to measure the spread of data (how much variability there is in the data) is to calculate the range. However, part (d) of problem 8‑30 shows that this measure may not provide a true sense of the spread.

A better way to measure the spread of the data is to calculate the mean absolute deviation. Read the Math Notes box in this lesson for an explanation of mean absolute deviation. Then follow the steps below to compute the mean absolute deviation for the basketball games.

Copy the table at right. Then use it to calculate the mean absolute deviation for Game 1 of problem 8-30 by following the steps below. Two of the rows are completed for you.

List the data values in the first column.

In the second column, list the differences when the mean is subtracted from each value.

List the absolute value of the differences in the third column.

Calculate the sum of the third column (the absolute values).

Divide the sum by the number of data values in the set to find the mean absolute deviation.

Data Value

Difference from Mean

Absolute Value

Sum: