Measures of Dispersion

Question 1

What is standard deviation?

Answer 1

• The distance of every value from the mean
• High = more variation and spread and less consistency around the mean
• Low = less variation and spread and more consistency around the mean

Question 2

What are the benefits of using standard deviation?

Answer 2

• More representative - includes all PPs scores whereas range only accounts for 2
• Only slightly affected by anomalous scores as measures the distance of each score from the mean - not as easily skewed by outliers

Question 3

What is range?

Answer 3

• Highest value - lowest value
• High = more variation and spread and less consistency
• Low = less variation and spread and more consistency in PPs scores/performance

Question 4

What are the cons of using range?

Answer 4

• Anomalous results will always be the highest/lowest value. Thus, as the range only focuses on the highest and lowest values of a data set it is easily skewed by outliers
• Unrepresentative - only focuses on highest and lowest values and doesn’t take all values into account