Significance level

Question 1

How do you see if our result is significant?

Answer 1

• Work out the probability that what we have found is due to chance.
• This is expressed as a value, p.
• The smaller the value of p is, the more significant your results are.

Question 2

What are the steps to find out if your data is significant?

Answer 2

• Collect your data
• Carry out a statistical test
• This gives you the calculated value
• Compare calculated value with the critical value in a statistics table
• Read the table to see if your data is significant, and if so, what level of significance (p)

Question 3

In psychology, what percentage do we usually aim to be sure that our results are due to a real effect?

Answer 3

• 95% sure
• 5% probability that the null is true
• This is expressed as p=<0.05. This is known as the significance level.
• So p=<0.05 means there is an equal to or less than 5% probability that our results are due to chance.

Question 4

What does it mean by ‘the results were significant at p<0.05’?

Answer 4

• This means that the result is significant at 0.05 level

- This means there is a less than 5% probability that the difference/relationship found was due to chance

Question 5

What is a type 1 error?

Answer 5

This is a false positive.

It is accepting the alternate when we should have accepted the null.

Question 6

What is a type 2 error?

Answer 6

This is a false negative.

It is accepting the null when we should have rejected it.