16 - Statistical Testing

Question 1

What are the two types of statistics?

Answer 1

Descriptive statistics

Inferential statistics

Question 2

Why is inferential statistics used?

Answer 2

To see if our results are significant in order to make an inference about the target population

Question 3

What do inferential statistics work out?

Answer 3

The probability that a particular set of data has occurred by chance, and not because of the independent variable.

Question 4

What is the value of the probability psychology uses?

Answer 4

p<0.05

Question 5

When do you use a sign test?

Answer 5

For paired or related data

Could be used for matched pairs design

Question 6

What are the steps to do a sign test?

Answer 6

1. State the hypothesis : directional , then one tailed. Non - directional then two tailed.
2. Record the data and work out the sign. Record difference between each pair of data. Use + if variable has increased, and - if variable has decreased.
3. Add up plus signs, and minus signs. The smaller value is S. This is called the calculated value.
4. N is the total number of scores ( ignoring 0 values). Use table of values to find critical value. S must be equal to or less than the critical value for it to be significant.
5. If this is the case, and it goes in the expected direction, then we accept the alternative hypothesis and reject the null hypothesis.