Chapter 3 - Measures of Center Flashcards
Measure of Center
A value at the center or middle of a data set.
Mean
The measure of center found by adding the data values and dividing the total by the number of data values.
Median
The measure of center that is the middle value when the original data values are arranged in order of increasing (or decreasing) magnitude.
Mode
The value that occurs with the greatest frequency.
Midrange
The measure of center that is the value midway between the maximum and minimum values in the original data set.
Finding the Midrange
Add the maximum data value to the minimum data value and then divide the sum by 2.
Weighted Mean Formula
When different x data values are assigned different weights w. See formula pg. 105.
Range
The difference between the maximum data value and the minimum data value.
Round-Off Rule
When rounding the value of a measure of variation, carry one more decimal place than is present in the original set of data.
Standard Deviation
The measure of how much data values deviate away from the mean. Formula pg. 114
Variance
The measure of variation equal to the square of the standard deviation.
Coefficient of Variation
For a set of nonnegative sample or population data is expressed as a percent and describes the standard deviation relative to the mean. Formula on pg. 123.
Z Score (Standardized Value)
The number of standard deviations that a given value x is above or below the mean. Formula pg. 130.
Percentiles
Measures of location, which divide a set of data into 100 groups with about 1% of the values in each group.
Quartiles
Measures of location which divide a set of data into four groups with about 25% of the values in each group.
