MOCT & MOD

• what can measures central tendency also be known as?

  averages.
• what are the measures of central tendency?

  mean, median, mode.
• mean

  Adding all of the numbers in the data together and dividing that by the number of elements in the data set.

  
  

  The mean is good as it includes all data in the set.
• median

  The term that is in the middle of the data set when it is ordered. If there is 2 middle terms you add them together and divide by 2.

  
  

  The median is not a true representation of the data set.
• mode

  The most common/most popular term in the data set. There can. be 2 modes (bimodal) but if there is more than 2 the set of data does not have a mode.

  
  

  The mode is not helpful when data is continuous.
• what do measures of dispersion look at?

  The spread of data around a central value - looks at the variety within results.

  (central values = mean; median; mode)
• what are the measures of dispersion?

  Range & standard deviation.
• range

  Take the smallest value away from the largest value and +1.

  
  

  Easy to calculate be does not represent all data.
• standard deviation

  Measures variability of scores around the mean (high value = higher diversity).

  x = number in data set

  _

  x = mean

  backwards Z =sum of. Add together all the answers from the number of data set - mean (squared).

  divide by N = number of data in the set.

  square root = square root the answer after dividing by N.

  
  

  Sensitive but can be distorted by extreme values.

  
• types of data matching measure of central tendency & dispersion

  data: measure of central tendency: measure of dispersion.

  nominal: mode: n/a

  ordinal: median: range

  interval: mean: standard deviation