Measures of central tendancy? Flashcards
What do measures of ct do?
inform us about central (or middle) values for set of data
What are measures of central tendency’s?
They are averages
Mean
Median
Mode
How is the mean calculated?
Add numbers and then divide by amount of numbers
Advantages of the mean?
Most sensitive amount of measurement as each number is being taken into account
Disadvantages of the mean?
Can be distorted by one or more extreme value so less representative
Can’t be used with nominal data
Doesn’t make sense when discrete values are used in average numbers of legs
What is the median?
The middle values in an ordered list. When all values are arranged the central value is the median
If their are 2 middle values you add them together and divide them by 2
Advantages of the median?
-Not affected by extreme scores so can be useful in any circumstance
-Appropriate for ordinal data and can be easier to calculate
Disadvantages of the median?
Not as sensitive exact values aren’t used
What is the mode?
The value that is the most common within data
If in nominal- its the data with the highest frequency count
-Modal group is the one with the highest frequency
-If 2 categories’ have the same frequency the data has two modes. Therefore its bi-modal
Advantages of modes?
-Unaffected by extreme values, more useful
-Much more usefull by discrete data
-The only method that can be used when data is in category i.e. nominal data
Disadvantages of modes?
-It’s not a useful way of describing data when there are several modes (like interval/ratio) data
The mean and levels for measurement?
interval and ratio data as it requires equal spacing between adjacent values or scores in the scale
The median and levels of measurement?
On ordinal, interval and ratio
The mode and levels of measurement?
can be used for any but mainly nominal and ordinal levels
