Descriptive statistics Flashcards
What are descriptive statistics
The use of graphs, tables and summary statistics to identify trends and analyse sets of data
What are measures of central tendency
A descriptive statistic that provides information about an ‘average’ value for a data set
What are three measures of central tendency
mean, median, mode
What is the mean
The arithmetic average of a data set that takes the exact values of all the data into account
What is the median
The middle value of a data set when the items are placed in rank order
What is the mode
The most frequently occurring value in a set of data
What are measures of dispersion
A descriptive statistic the provides information about how spread out a set of data are
What are the two measures of dispersion
Range and standard deviation
What is the range
The difference between the highest and lowest item in a data set
What is standard deviation
A more sophisticated measure of dispersion. Tells us how much scores deviate from the mean. All differences are added up and divided by the number of scores. This gives a variance and then this is square rooted.
What is a strength of using the mean
Most sensitive measure of central tendency- takes account of exact distance between all the values of all the data
What is a limitation of using the mean
Easily distorted by extreme values= misrepresentative of the data as a whole
What is a strength of using the median
Not affected by extreme scores and easy to calculate
What is a limitation of using the median
Less sensitive than the mean- not all items are included in the final calculation (such as outliers/extreme scores)
What is a strength of using the mode
More useful for nominal (categorical) data
