Steps 3 & 4 (Evaluate & Decide) of NHST

Question 1

When do we reject the hypothesis H0?

a. When p > 0.05
b. When p < 0.05

Answer 1

b. When p < 0.5

Question 2

H0 = There is no difference between UoM student’s mean maths score and the mean maths score of the whole UK uni student pop.

After data collection, we found that the probability of getting a result higher than the one we’ve got is small.

Do we reject or fail to reject H0 and why?

Answer 2

We reject H0

Because there’s only a small chance that we’d get results that are much higher than the one we’ve got

This suggests that our score is so high that barely any other score can beat it (hence, the probability of achieving anything higher than what we’ve got is small)

This is inconsistent with H0, which claims that our sample mean score and pop. mean score has no difference

So because it is inconsistent with H0 and consistent with H1, we reject H0

Question 3

H0 = There is no difference between UoM student’s mean maths score and the mean maths score of the whole UK uni student pop.

After data collection, we found that the probability of getting a result higher than the one we’ve got is large.

Do we reject or fail to reject H0 and why?

Answer 3

Fail to reject H0

Because there’s a big chance that we’d get results that are much higher than the one we’ve got

This suggests that our score is pretty average/not very high that a lot of other scores can be higher than it (hence, the probability of achieving anything higher than what we’ve got is large)

This is not inconsistent with H0, which claims that our sample mean score and pop. mean score has no difference

So because it is not sufficiently inconsistent with H0 and is not consistent with H1, we fail to reject H0

Question 4

When do we fail to reject the hypothesis H0?

a. When p > 0.05
b. When p < 0.05

Answer 4

a. When p > 0.05

Question 5

In NHST finding that p < 0.05 means we can reject the null hypotheis and so our research hypothesis is correct

a. True
b. False

Answer 5

a. False

Yes we reject H0 but that does not mean H1 is correct (we only found evidence supporting H1 not proving it)

Question 6

Fill in the blank

In Step 3 of NHST we need to evaluate the
(……….) between our data and the (………….)

Answer 6

1) Inconsistency
2) Null hypothesis

Question 7

Fill in the blank

In practice, this is equivalent to calculating the
(……….) of having obtained a sample statistic in a particular region if we (…………) that the (…………) is (………….)

Answer 7

1. Conditional probability
2. Assume
3. Null hypothesis
4. Correct