Analysis of Variance (ANOVA)

Question 1

What is the normal distribution?

Answer 1

When the distribution has observed values being most probable at some average, and increasingly less probable for values further away from that average.

Question 2

What are the parameters for the normal distribution?

Answer 2

The mean.
The standard deviation.

Question 3

When the null hypothesis is true, the two populations are mostly __________. When it isn’t, there is minimal ______.

Answer 3

Overlapping, overlap.

Question 4

What does “chance” refer to?

Answer 4

All uncontrolled sources of variability in an experiment.

Question 5

What are the 2 main types of experimental error?

Answer 5

1. Individual difference error
2. Measurement error

Question 6

What makes individual differences error more extreme?

Answer 6

Small sample sizes.

Question 7

What is the F-ratio?

Answer 7

The ratio of the between groups deviation to the within groups deviation.
(Treatment effect + Experimental error) / Experimental error.

Question 8

If the null hypothesis is false, the F-ratio should be ____. How do we test this?

Answer 8

Large.
We test this by comparing it to the F-distribution.

Question 9

ANOVA uses the ratio of ______ and _______ to test the null hypothesis.

Answer 9

Between-groups deviation, Within-groups variation.

Question 10

What are the 4 assumptions of ANOVA?

Answer 10

1. The DV is on an interval/ratio scale
2. The DV is normally distributed
3. The DV has equal variances in the population
4. The estimates of the population variance are independent

Question 11

Our goal in ANOVA is:

Answer 11

To determine whether an observed difference in sample means can be generalised to population means, given our uncertainty about these.

Question 12

What is the F-distribution?

Answer 12

It gives an estimate of the probability of observing a particular F-ratio by chance, given the sample size and number of groups.