1.4 One way ANOVA

Question 1

what is analysis of variance (ANOVA)

Answer 1

a statistical technique that is used to test for the significance of hypothesized group means difference

Question 2

What type of data is ANOVA useful for? How many group means can you compare with ANOVA

Answer 2

experimental data
2 or more

Question 3

In ANOVA the IV is referred to as?

Answer 3

factor

Question 4

The conditions or groups of a factor are referred to as?

Answer 4

level of a factor

Question 5

some important terms for ANOVA

Answer 5

Within-subject and between-subject variables
within-groups variations and between-groups variation

Question 6

Analysis of variance (ANOVA) includes several different types of analyses, including

Answer 6

-One-way ANOVA,
-Factorial ANOVA,
-Repeated measures ANOVA for within-subjects data includes one or more factors
-Mixed ANOVA
-Analysis of covariance (ANCOVA)
-Multivariate analysis on variance (MANCOVA)

Question 7

one-way ANOVA

Answer 7

used to compare two or more means of a single factor
involved assessing the effects of a single factor (IV) on the scores of a single dependent variable \
factor is categorical
DV is continuous

Question 8

Factorial ANOVA

Answer 8

for between-subject data includes two or more factors (IVs)

Question 9

Mixed ANOVA

Answer 9

includes both between-subject and within-subject factors

Question 10

Analysis of covariance (ANCOVA)

Answer 10

is an extension of ANOVA that includes covariates as control variables

Question 11

Multivariate analysis on variance (MANCOVA)

Answer 11

is an extension of ANOVA that allows for more than one dependent variable

Question 12

in an ANOVA, If the factor has three or more levels, then the initial analysis is referred to as?

Answer 12

omnibus F test

Question 13

in ANOVA what does a significant F ratio indicate?

Answer 13

that there are likely differences among the level means, but it does indicate which means are different
Follow-up analysis are needed to specify level differences

Question 14

what is the F ratio? And what is its basic question

Answer 14

a signal to noise ratio…
The basic question is, is the variation between groups larger than the variation within groups?
If it is, then that difference is due to the treatment effect

Question 15

Questions answered with one-way ANOVA
(list three at least)

Answer 15

Are there differences among the group means?
F ratio and p value
How large are the differences?
Eta squared effect size
How powerful was the F test?
What are the group means, standard deviations, and or standard errors?
What are the 95% confidence intervals that surround the group means?
Graphical representation of means

Question 16

In ANOVA The null hypothesis (H0) is expressed as:

Answer 16

H0: µ1=µ2=µ3=…=µk
States that there are no difference level means

Question 17

Alternative hypothesis (HA):

Answer 17

HA” “one or more levels is/are different”
No equation is needed

Question 18

F ratio, which if it is large enough indicates. what is F ratio formula?

Answer 18

significant differences among group means
F=MSb/MSw
F= Inherent variance+treatment effect/inherent variance

Question 19

Mean square error (within groups) and treatment (between groups)

Answer 19

MSb=SSb/dfb ; MSw=SSw/dfw

Question 20

Degrees of freedom error (within groups), treatment (between groups), and total

Answer 20

dfb=K-1
dfw=k(n-1)

Question 21

what is normality an assumption of?

Answer 21

that the distribution of the dependent variable are normally distributed for all levels of a factor

Question 22

what indicates a violation of normality assumption?

Answer 22

Excessive skew or kurtosis indicate violations of the assumption
If distributions of all groups are non-normal in the same way, then violation is unlikely to have much of an effect

Question 23

Homogeneity of variance

Answer 23

The variance among the three groups are not different from one another
o1=o2=o3=oe
Where e is the common variance between three conditions
ANOVA is usually robust to fairly large violations of the assumption
SPSS provides a test of this assumption

Question 24

Partition of Sum of Squares(Variability)

Answer 24

SStot can be divided by in two part SSw and SSbet