Descriptive Statistics - Chapter 3

Front 1

Measures of Central Tendency

Back 1

A set of methods to help identify the properties of numerical variables that group around a specific value.

Front 2

The Mean

Back 2

A number equal to the doctor of the data values, divided by the number of Data values that were summed.

Front 3

The Median

Back 3

The middle value when a set of the data values have been ordered from lowest to highest value. When the number of Data values is even, no natural middle value exists and you perform a special calculation to determine the median.

Front 4

Measures of Position

Back 4

Describes the relative position of a data value of a numerical variable to the other values of the variable. Statisticians often use to compare two sets of data values.

Front 5

First Quartile, Q1

Back 5

The value such that 25% of the ranked data values are smaller and 75% are larger.

Front 6

Second Quartile, Q2

Back 6

Another name for the median

Front 7

Third Quartile, Q3

Back 7

Is the value such that 75% of the ranked values are smaller and 25% are larger.

Front 8

Variation

Back 8

Show the amount of dispersion in the data values in a set of data values.

Front 9

Dispersion

Back 9

Spread

Front 10

The Range

Back 10

The difference between the largest and smallest data values in a set of data values.

Front 11

The Variance and Standard Deviation

Back 11

Two measures that tell you how a set of data values fluctuate around the mean of the variable. The standard deviation is the positive square root of the variance.

Front 12

Standard (Z) Score

Back 12

The number that is the difference between a data value and the mean of the variable, divided by the standard deviation.

Front 13

Symmetrical Shape

Back 13

A set of data values in which the mean equals the median value and each half of the curve is a mirror image of the other half of the curve.

Front 14

Left-Skewed Shape

Back 14

A set of data values in which the mean is less than the median value and the left tail of the distribution is longer than the right tail of the distribution. Also known as negative skew.

Front 15

Right-Skewed Shape

Back 15

A set of data values in which the mean is greater than the median value and the right tail of the distribution is longer than the left tail of the distribution. Also known as positive skew.

Front 16

The Box-and-Whisker Plot

Back 16

For a set of data values, the five numbers that correspond to the smallest value, the First Quartile Q1, the median, the Third Quartile Q3, and the largest value.