Measures of dispersion

• What are the two measures of dispersion?

  Range and standard deviation
• How is the range calculated?

  Biggest number minus smallest number
• What are the steps to calculate standard deviation?

  1. Calculate the mean of scores
  2. Subtract the mean from each score
  3. Square each difference
  4. Sum the squared differences
  5. Divide by the number of scores minus one
  6. Take the square root of the result
• What is the first step in calculating standard deviation?

  Calculate the mean number of scores
• What do you do after calculating the mean in standard deviation?

  Subtract the mean from each score
• What is done with the differences after subtracting the mean?

  Square each difference
• What do you do after squaring each difference in standard deviation calculation?

  Add up each of the squared data
• How do you find the variance in the standard deviation process?

  Divide by the number of scores minus one
• What is the final step in calculating standard deviation?

  Find the square root of the value