Descriptive Statistics (RM) Flashcards
What is the mean?
An arithmetic average of a set of scores calculated by diving the sum of scores by the number of scores
What are the strengths of a mean?
It takes all scores into account so is the most sensitive measure
What are the limitations of a mean?
Easily distorted by extreme scores, making it unrepresentative (the median may be more representative)
Can give a peculiar measure that Connor represent reality
What is the median?
The middle values of a set of scores
What are the strengths of the median?
More representative that the mean (especially with small data sets)
Unaffected by extreme scores in one direction
What are the limitations of the median?
Less representative when the data set is polarised
What is the mode?
The most frequently occurring value in a set of scores
What are the strengths of the mode?
Unaffected by extreme scores
Most useful with large data sets
What are the limitations of the mode?
Unreliable for use with small data sets as small changes to score can result in it being multimodal
What is the range?
A measure of dispersion that is the difference between the highest and lowest score in a data set
What are the strengths of the range ?
Easy to calculate and give an indication
Useful when the median is being used as an average as the range uses the top and bottom of a set and the median is the middle number
What are the limitations of the range?
Easily distorted by extreme scores
Only uses two numbers from a data set no matter how large the data set is so is a basic indicator of spread at best
It gives not indication of the spread of scores within a data set
What is standard deviation?
A measure of dispersion that shows how much each score in the data set deviates on average from the mean of that data set
What are the strengths of standard deviation?
Uses all scores in a data set in its calculations
It gives a sensitive measure of how all scores are dispersed around the means
It is a powerful statistic with applications elsewhere
What are the limitations of standard deviation?
More difficult to calculate than the range
As it uses the mean, it can be distorted by extreme scores
