1-Way Anova

Question 1

Definition of Anova

Answer 1

Anova examines if there is a statistically significant difference in the means of two or more groups or conditions.

Question 2

What are the types of designs used in an anova?

Answer 2

Between-subjects anova (independent) = different participants are used in each condition
within-subjects anova (related) = the same participants are used in each condition.

Question 3

What is parametric?

Answer 3

Parametric test means it makes assumptions about the distribution of the scores. The assumptions include:

• level of measurement must be interval or ratio.
• Scores should be normally distributed
• homogeneity of variance - meaning data in each group should have the same variance.
• observations should be independent - so no collusion

Question 4

What is the characteristic of anova?

Answer 4

Anova is fairly robust so an anova can be still used on data if it doesn’t meet all the assumptions.

Question 5

advantages of anova

Answer 5

• anova means you don’t have to do multiple t-tests which increases the chance of type 1 error occurring which is a false positive.
• a factorial anova allows for multiple independent variables (factors) to be investigated at the same time.

Question 6

What is a type 1 error?

Answer 6

Type 1 error is a false positive which means the null hypothesis is rejected when it is actually true.

Question 7

Definition of factorial anova

Answer 7

A factorial anova is an anova that investigates multiple factors (independent variables) at the same time.

Question 8

Definition of Factor

Answer 8

Factor in anova is independent variable

Question 9

Definition of levels

Answer 9

Levels of a factor is the groups/conditions of an independent variable.

Question 10

What does the p value have to be for the difference to be considered significant

Answer 10

p value has to be less than 0.05 to be considered significant.

Question 11

What does an anova do?

Answer 11

anova finds out if there is a statically significant difference in the mean between two or more groups by calculating the f ratio which compares variation by comparing explained variation due to manipulation of Independent variable (ms treatment) and unexplained variation due to individual differences (ms error)

Question 12

MS error

Answer 12

MS error is unexplained variation due to individual differences in f ratio.

Question 13

MS treatment

Answer 13

Ms treatment in f-ratio is explained variation due to manipulation.

Question 14

Why does an anova allow you to avoid doing multiple t-test?

Answer 14

Factorial anova allows you to investigate multiple independent variables (factors) at the same time.

Question 15

How do you report degrees of freedom in anova?

Answer 15

You report 2 degrees of freedom in an anova. You report smaller one first.

Question 16

what does ANOVA stand for?

Answer 16

ANOVA means analysis of variance

Question 17

How does you report a 1-way anova?

Answer 17

a 1-way between subjects analysis of variance (ANOVA) revealed a statically significant effect of task, F (12, 36) = 0.29 p = 0.02.

Question 18

How many levels can a factor have in an anova?

Answer 18

A factor in an anova can have 2 or more levels.

Question 19

what is equation for f ratio?

Answer 19

f = ms treatment/ms error
ms treatment = variation due to manipulation of independent variable.
ms error = variation due to individual differences.

Question 20

Disadvantage of ANOVA

Answer 20

• F ratio tells you whether there is a difference but it does not tell you whether the difference is. so you have to do post hoc test to find out where the difference lies.
• anova cannot be done on all data as anova is parametric so data has to meet parametric assumptions but anova is fairy robust so you can have minor departures from the assumptions.

Question 21

How to perform 1-way between subjects anova in SPPS?

Answer 21

To perform a 1 way anova in spss you press analyse, compare means and one way anova.

Question 22

When do you report levene’s test (homogeneity of variance)?

Answer 22

You report levene’s test if it is significant so less than 0.05

Question 23

How to perform one way within subjects anova on SPSS?

Answer 23

To perform a 1-way within subjects anova you press analyse, general linear model and repeated measures