In this video lecture, Professor Naomi Lowe explains measures of central tendency and variability.
N represents the total number in a sample, M is the mean, X represents the variable of interest, and S denotes summation. The mean is the sum of all the scores divided by the total number of scores.
The median is the middle score when all scores are arranged from lowest to highest. Median is used instead of a mean when there are extreme outliers.
The mode is the most common single number in a set of scores. This is a measure of central tendency of nominal variables. Data can have no modes or multiple modes.
Outliers affect the mean but not the median. Extreme scores alter the symmetry and shape of graphs. When the median and mean are equal the data is symmetrical.
Lowe reviews the formula for variance and outlines the five steps to calculating variance. Standard deviation is an average of how far values are from the mean.
Standard deviation is the most common way to describe the spread of scores. Steps for computing standard deviation include calculating variance followed by taking the square root of the variance. Lowe reviews the formula for standard deviation.
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In this video lecture, Professor Naomi Lowe explains measures of central tendency and variability (spread).
Length: 30 minutes
Copyright date: ©2010
Prices include public performance rights.
Not available to Home Video and Publisher customers.
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