Statistical inference

Question 1

What is the difference between t-distribution and normal distribution?

Answer 1

For a 95% confidence interval, we need to replace the key number 1.96 with a larger number and that depends on the sample size

Question 2

How many degrees of freedom do we use?

Answer 2

n-1 where n is the sample size

Question 3

What does a 95% confidence interval mean?

Answer 3

A 95% confidence interval for the μ will contain the true value of μ 95% of the time

Question 4

What is a p-value?

Answer 4

A measure of probability that tells us how likely we would be to see a sample as more extreme if the null hypothesis were true

Question 5

What do small p-values mean?

Answer 5

Tell us that the sample we have observed would be unlikely to have occurred if the null hypothesis is true thus a small p-value is evidence against the null hypothesis

Question 6

What do we do if p>0.05?

Answer 6

Do not reject as there is no evidence against H0

Question 7

What do we do if p<0.05 but p>0.01?

Answer 7

Reject at the 5% level as there is moderate evidence against H0

Question 8

What do we do if p<0.01 but p>0.001?

Answer 8

Reject at the 1% level as there is strong evidence against H0

Question 9

What do we do if p<0.01?

Answer 9

Reject at the 0.1% level as there is very strong evidence against H0