measures of central tendency and dispersion

• range-describes the differencebetween the lowest and the highest scores in a data set

  • strengths: Easy to calculate
  • provides a broad overview of the data which can be useful for some research purposes
  • limitations: Affected by extreme values
  • it isnt very representative as it doesnt show distribution of scores
  • Use with: ordinal or highly skewed
• Strength and limitation of mean 

  • Most sensitive measure of central tendency as it takes into account all numbers and the exact distance between all values of all the data
  • Can be easily distorted by extreme values and can’t be used with nominal
• Strength and limitation of median 

  • Appropriate for ordinal and not affected by extremes menaing to gives an accurate representation of the typical value compared to the mean,(used to describe non normal distributions)
  • Exact values not reflected in final calculation - not as sensitive 
• Strength and limitation of mode 

  • Unaffected by extreme values and is only measures applicable to categories
  • Not useful with several modes and doesn’t tell us anything about other values in the data set
• Strength and limitation of standard deviation

  • precise as it take all exact values into account and how the scores are distributedacross a data set
  • may hide some characteristics like extreme values
  • difficult to calculate, does not show the full range of the data
• what does the standard deviation suggest about the scores

  in teh group... there was a much larger spread of scores -this means this group was less similar in their scores - didn't work for everybody-there are varaition in invidual differences
• why is the standrard deviation better than the range

  it takes into account all of the scores