descriptive statistics

• nominal data- mode, pie-chart or bar-chart


  = data in categories that is tallied (number of ps who listen to music on a phone, laptop or tv)
• ordinal data - median > bar-chart but scattergram for correlation

  = data where each p has a score that can be ranked in order
• interval data- mean> histogram but scattergram for correlation


  = an already existing, universal, precise measurement with equal units (temp , distance , time)
• histograms

  x axis = frequency, mean, %

  y axis = measurement scale
• mean


  :) takes all values into account

  :( distorted by extreme values
• median

  :) simple

  :) not distorted by extreme values

  :( doesn't take all values into account
• mode

  :) simple

  :( may have multiple modes = meaningless
• range

  :) simple

  :( doesnt include all data
• standard deviation

  the spread of data around the mean

  -low SD = closely clustered

  -high SD = widely spread

  -SD of 0 = all numbers are the same

  :( requires the mean and is difficult to calculate