Distribution

Question 1

What is distribution?

Answer 1

The pattern of frequencies for each score from a set of participants (how many people gained each score)

Question 2

What are the features of a normal distribution?

Answer 2

1) mean, median and mode are all in exact midpoint and are (nearly) identical values
2) distribution of scores around midpoint is symmetrical
3) distribution of scores either side of midpoint are consistent and expressed in standard deviations
4) bell shaped curve

Question 3

In normal distribution, what percentage of people are 1 standard deviation above and below average?

Answer 3

68.2%

Question 4

In normal distribution, what percentage of people are 2 standard deviations above and below average?

Answer 4

95.4%

Question 5

What are the features of a positively skewed distribution?

Answer 5

1) trend towards low end of score spectrum
2) mode lowest, then median, then mean

Question 6

How would you make a positive skew more normal?

Answer 6

Make test easier so people score higher

Question 7

What are the features of a negatively skewed distribution?

Answer 7

1) averages clustered towards high end of spectrum
2) mode highest, then median, then mean

Question 8

How would you make a negative skew more normal?

Answer 8

Make test harder so people score lower