Central Tendency And Dispersion Flashcards
What is mean
Adding up all data items and dividing them by the number of data items
Advantages of mean
Takes account the exact distance of all values
Disadvantages of mean
Very sensitive, it can easily be distorted by one extreme value
Misrepresent I’ve
Cannot be used with nominal data
What is median
The middle value in an ordered list that are all arranged in order
Advantages of median
Not affected by extreme scores
Appropriate for ordinal data
Easier to calculate
Disadvantages of median
Not as sensitive
Exact values are not reflected in the median
What is mode
The most common data item
Advantages of mode
Unaffected by extreme values, More useful for discrete data
Only method that can be used when the data is in categories eg nominal data
Disadvantages of mode
Not a useful way of describing data when there are several modes
What are measures of dispersion
When the data is spread out
What is range
The distance between the top and bottom values in a set of data
Advantages of range
Easy to calculate
Disadvantages of range
Affected by extreme values
Doesn’t take into account distribution of numbers
What is standard deviation
A measure of the average distance between each data item and below the mean
Advantages of standard deviation
Précise measure of dispersion
Not difficult to calculate with a calculator
