6th Gr. Numerical Summaries of Data

Measure of center

tells you how data values cluster, or where the "center" of the data is.

Median

is the middle number in a data set when you place the values in order from least to greatest or greatest to least

Balance point

When you have all the points at the same value, you balance the number line.

Mean

is the arithmetic average of the numbers in a data set. You calculate the mean by adding all of the values in the data set and dividing the sum by the number of values.

Quartile

are the numbers that split data into quarters (or fourths).

Measure of variation

describes the spread of data values. One measure of variation is the range.

Interquartile range

is the difference between the third quartile and the first quartile, or Q3 - Q1. The IQR indicates the range of the middle 50 percent of the data.

Box-and-whisker plot

is a graph that displays the five-number summary of a data set. Also called a box plot.

Deviation

of a data value indicates the distance of a data value from the mean.

Absolute deviation

the absolute value of each deviation.

Mean absolute deviaion

is the mean of the absolute deviations.