descriptive statistics

• what are descriptive statistics ?

  how to analyse data
• what are the two descriptive statistics ?

  measures of central tendency / measures of dispersion
• what are measures of central tendency and what are the 3 ?

  averages that tell us about the middle value In the data set 1. mean 2. median 3. mode
• what is the mean and evaluation?

  add all together then divide by how many + most representative - harder to calculate, not used on nominal data, effected by extreme scores
• what is median and evaluation?

  rank all data in order of highest to lowest then the middle value + not affected by extreme scores, easier to calculate than mean - less representative
• what is the mode and evaluation?

  most frequent + easy to calculate, unaffected by extreme values - doesn't use all the scores
• what are measures of dispersion and what are the 2 ?

  variability within the dataset. 1. range 2. standard deviation
• what is range and evaluation?

  subtract the lowest value from the highest. higher the range the more variation there is + shows overall spread, easy to calculate - not representative if there are extreme values
• what is standard deviation and evaluation?

  tells you the spread of data around the mean and the relationship between scores + representative, how individual scores relate to others and the mean - harder to calculate than range