Maths stuff

Question 1

What is a negative skew?

Answer 1

Majority of data on the right of the graph, mean then median then mode (left to right)

Question 2

What is a positive skew?

Answer 2

Majority of data on the left of the graph, mode then median then mean (left to right)

Question 3

When to use the sign test?

Answer 3

Looking for difference rather than an association
Repeated measures design has been used
Uses nominal data

Question 4

How to carry out the sign test?

Answer 4

1. Work out whether there is a positive or negative difference in each row
2. Add up total number of +s and -s (ignore any with no difference)
3. Assign S and N values. S is less frequent value, the N is the total number of values that aren’t 0
4. Plot your N value on the critical values table, assume level of significance is 0.05 unless told otherwise.
5. Your S value has to be equal to or less than the critical value to be significant.
   Present answer as S (x) > or < Critical Value (y)