lesson 14 - central tendency and dispersion

define descriptive statistics

the use of graphs, tables and summary statistics to identify trends and analyse data

define measures of central tendency

general term for any measure of the average value in a set of data

define measures of dispersion

general term for any measure of the spread or variation in a set of data

define standard deviation

measure of dispersion - how much scores deviate from the mean, all differences added up and divided by the number of scores giving a variance . the standard deviation is the square root of the variance

strength and limitation of range

easy to calculate

affected by extremes, ignores middle values

strength and limitation of standard deviation

uses all data, less affected by extremes

harder to calculate