# Post-hoc and Planned Comparisons Flashcards Preview

## PS3021 Stats > Post-hoc and Planned Comparisons > Flashcards

Flashcards in Post-hoc and Planned Comparisons Deck (16)
1
Q

When are post-hoc tests used?

A

Only if an ANOVA was significant.

2
Q

What are contrasts used for?

A

To evaluate specific predictions.

3
Q

What are post-hoc tests used for?

A

To explore what is going on.

4
Q

What does a Bonferroni correction take as C?

A

Number of corrections.

5
Q

What does Scheffe’s correction take as C?

A

Number of possible linear combinations.

6
Q

What does Sidak’s correction take as C?

A

Number of pairwise comparisons.

7
Q

Using the studentised range distribution, what decreases the critical value?

A

Increasing sample size.

8
Q

Using the studentised range distribution, what increases the critical value?

A

Increasing the number of levels/means you are comparing.

9
Q

When should Tukey’s HSD be used?

A

When there are a large number of levels in a factor.

10
Q

What are deviation contrasts?

A

Deviation of each level mean from the grand mean.

11
Q

What are simple contrasts?

A

Deviation from a reference mean.

12
Q

What are repeated contrasts?

A

Mean 1 vs. 2, 2 vs. 3, etc.

13
Q

What are polynomial contrasts?

A

14
Q

What are difference contrasts?

A

Compares each level with the average of all previous levels.

15
Q

What are Helmert contrasts?

A

Compared mean at each level with the average of all the subsequent (higher) levels.

16
Q

Give 3 orthogonal contrasts.

A

Polynomial, difference, and Helmert.