ANOVA exam

The degrees of freedom between groups for the interaction

(dfA x B) is dfA times dfB

Which is correctly written: 1. F(83)=# 2. F (83, 84)=# 3. T (78, 43)= #

2

The statistic for the ANOVA is

F

When ___is significant, it indicates that across all group means, there is a significant difference due to the independent variable.

Fobt

The degrees of freedom total equals

N - 1

The degrees of freedom within groups equals

N - kA x B

The critical value of F (Fcrit) depends on

The degrees of freedom (both the dfbn = k - 1 and the dfwn = N - k) The α selected

This type of variability tells us if our independent had an effect on our dependent variable.

between groups variability

how do 0mg scores differ from 10 mg scores, etc. look at different levels. Can also compare grand mean ( mean of all levels combined) how does the mean of 5mg differ from the grand mean?

between groups variablity

the degree to which the scores of different treatment groups differ from one another or the grand mean.

between groups variablity

show the second factor on a graph by

drawing a separate line connecting the means for each level of that factor

When there are more than two means in an experiment, using multiple t-tests results in an

error rate much larger than the one we have selected (α).

An independent variable is called a

factor

The independent variable matches which of the following ANOVA terms?

factor

hypothesis for ANOVA

ho: m1=m2=m3 ha: not all m's are equal

Lines cross:

interaction

When graphed, a significant interaction effect produces two or more lines that

intersect

dependent variable must be in what measurement

interval or ratio (scale)

The symbol for the number of levels in a factor is

k

The degrees of freedom between groups for factor A is

kA - 1

The degrees of freedom between groups for factor B is

kB - 1

Each condition of the independent variable is also called a ___ or a ____

level, treatment

the F test is a one or two tailed test

one

performed when only one independent variable is tested in the experiment

one-way anova

along the X axis,

place the levels of one factor

ANOVA does not indicate which

specific means differ significantly

along the Y axis

the dependent variable means

Using the ANOVA allows us to compare the means from all levels of the factor and keep

the error rate equal to α.

the effect that changing the levels of that factor has on dependent variable scores, while ignoring all other factors in the study.

the main effect of a factor

differences produced by the independent variable are a

treatment effect

When an experiment design has two factors but one factor involves related samples while the other factor involves independent samples, we should perform a

two way anova, mixed design

is present when the relationship between one factor and the dependent scores changes as the levels of the other factor change.

two way interaction effect

performed when two independent variables are tested in the experiment

two-way anova

When both factors involve independent samples, we perform the

two-way, between-subjects ANOVA

When one factor is tested using independent samples and the other factor using related samples, we perform the

two-way, mixed-design ANOVA

When both factors involve related samples, we perform the

two-way, within-subjects ANOVA

When the F-test is significant,

we perform post hoc comparisons on all pairs of treatment groups.

when do we use analysis of variance

when data are interval or ratio level and there is at least one independent variable with three or more levels.

variability within a single level. Thus, variability between participants JUST in the 0 mg level.

within groups

the degree to which the scores of subjects in the same treatment group differ from each other

within-groups variablity

When an experimental design has two factors and both factors are tested using related samples, we should perform a

within-subjects two way anova

refers to the interaction between the two factors

A x B

Assumptions of ANOVAs

All conditions contain independent samples The dependent variable measures normally distributed interval or ratio scores The variances of the populations are homogeneous

what does ANOVA stand for

Analysis of variance