Distributions

Question 1

Normal distribution

Answer 1

The mean, mode and median are all equal

Question 2

Negative skew

Answer 2

Hugh mode, middle median and low mean. On a graph it is negatively skewed to the left

Question 3

Positive skew

Answer 3

Low mode, middle median, high mean. On graph it is positively skewed to the right.

Question 4

What different reasons might explain skewed data

Answer 4

1 - TEST/ QUESTIONNAIRE
too hard - causes positive skew
too easy - causes negative skew

2 - OUTLIERS
score that is too high - causes positive skew
score that is too low - causes negative skew

3 - SAMPLE BIAS
opportunity and volunteer sampling get similar types of people

Question 5

How would you remove the problems causing skewed data

Answer 5

• mix of easy and hard questions
• remove outliers
• use random or stratified sampling