measures of dispersion/ central tendency

why is it most appropriate to use the mean?

there are no extreme values (not skewed) so distortion will not be a problem with this data set

the mean takes into account every value/ uses all the data SO is more representative of the data than other measures

data (e.g is in time) and so therefore is interval data

when is median most appropriate?

not effected by extreme scores as would be if it were the mean used

when is mode not appropriate

sometimes each score only appears once (no multiple sets/ most common) or sometimes there may be multiple modes which also is not useful

limitation of using the range 

the range only takes into account the highest and the lowest value and this can not be very accurate as to what the data set actually looks like 

limitation of using standard deviation

calculation of SD is based on the mean, it can be distorted by a single extreme value this means it will not give a true indication of how the scores are dispersed