Lecture 27- P Value

Question 1

How do we interpret a P value between 0.01 and 0.05?

Answer 1

‘There is some evidence that we should reject H0’

Question 2

How do we interpret a P value below 0.01?

Answer 2

‘There is strong evidence that we should reject H0’

Question 3

What does choosing a smaller significance level mean?

Answer 3

It becomes more and more unlikely that you would get this result/ something more extreme if the null hypothesis was true. Therefore, have stronger evidence to reject the null.

Question 4

What is it called when we reject the null hypothesis but it is actually true?

Answer 4

Type 1 error, random error/ chance just means we got a very rare result for the null hypothesis distribution it still stands though.

Question 5

What is a type 2 error? What the chance of this depend on?

Answer 5

We incorrectly retain the null hypothesis when it is false. Should have gone for the alternative hypothesis instead. Chance of this depends on sample size.

Question 6

What’s the difference between statistical and meaniful significance?

Answer 6

• Statistical significance means the P value is below the significance value and therefore we have found something interesting (not due to chance)
• Meaningful significance means there is a practical application of these findings. The size of the effect is large enough to have an impact.

Question 7

Go through example on slide 524 and 525 about determining inconclusive/ conclusive results and significance?

Answer 7

Answers in notes + on the following slides

Question 8

What value does an inconclusive confidence interval contain?

Answer 8

0