measures of central tendency / dispersion

strengths of using a median

It is not impacted by extreme (anomalous) data

strengths of mean

uses all the data in its calculation so is most representative of the data as a whole

strength of mode

easy to calculate - sometimes the only option e.g for data in categories.

weakness of mode

not representative of whole data. also, not very useful if several modes.

weakness of median

it ignores extreme data, but this may be important

weakness of mean

it is easily distorted by extreme values which may not represent the data as a whole well

measures of central tendencies

measures that give averages e,g mean, mode, median

descriptive statistics

the use of graphs tables and summary statistics to identify trends and analysis sets of data.

measures of dispersion

the general term for any measures of the spread or variation in a set of scores

strength of range

easy to calculate and by adding 1 can account for a margin of error

range

take the lowest score from the highest score and usually add 1 to account for the fact the much of data is rounded up/down so accounts for a margin of error

range weakness

only takes into account the most extreme variables so may be unrepresentative of the data as a whole

standard deviation

a single value that tells you how far scores deviate from the mean. The larger the standard deviation the great the spread of values within a data set. e.g. a low standard deviation means pets generally responsed in the same way.

standard deviation strength

it is a more precise measure of dispersion as it includes all the data in its calculation so more representative

standard deviation weakness

easily skewed by anomalous data and doesn’t represent extreme score which may be important