Data Distributions

Question 1

What are the three types of distribution?

Answer 1

• Normal distribution
• Positive skewed distribtuion
• Negative skewed distribution

Question 2

What are the characteristics of the normal distribtuion?

Answer 2

• Classic, bell shaped curve
• Mean median and mode are all at the exact midpoint
• The distribution is symmetrical around midpoint
• The dispersion of scores either side of midpoint is consistent and can be expressed in standard deviations

Question 3

What percentage of data is within 1, 2 and 3 standard deviations of the mean in a normal distribution?

Answer 3

• 68% within 1 s.d
• 95% within 2 s.d
• 99.7% within 3 s.d

Question 4

What is a skewed distribution?

Answer 4

• One tail is longer than another, signifying that there are a number of extreme values to one side or the other of the mid-score
• The distribution leans to one side or the other

Question 5

What would a positive and negative skew look like?

Answer 5

• Positive has scores bunched to the left
• Negative has scores bunched to the right