measures of central tendency and dispersion Flashcards
measures of central tendency
descriptive stats include measures of central tendency
these measures are average which give us info about the most typical values in a set of data
mean , median and mode
mean
average
calculated by : adding up all the scores or value in a data set anf dividing it by the total number of scores there are
the mean is the most sensitive of the measures of central tendency as it includes all f the scores/vlaurs in the data set within the calculation means it is more representative of the data as a whole
it is easily distorted by extreme values
median
middle value in a data set when scores are arranged form lowest to highest
extreme scores don’t effect it
less sensitive than the mean as the actual values of lower and higher number are ignored and extreme values may be important
mode
most frequently occurring score/value within a data set
measures of dispersion
based on the spread of scores
how far scores vary and differ from one another
range
taking the lowest value form the highest value and usually adding 1
easy to calculate
only takes into account the two most ecxtreme values and this may be unrepresentiave of the data set as a whole
range is influence by outliers
standard deviation
single value that tells us how far scores deviate from the mean
larger the deviation the greater the dispersion or spread within a set of data
if we are talking about a particular condition within an experiment a large standard deviations biggest that nit all participants were affected by the IV in the same way because the data is quite widely spread
may be that there are a few abomoalus results
a low standard deviation value reflect the fact that the data is tightly clustered around the mean which might imply that all participants responded in a fairly similar way
much more precise measure of dispersion than range is as it include all values within the final calculation
can be distorted by an extreme values
