PSYC 4400 Final

positively skewed

Is the distribution of possible outcomes for the test statistic positively or negatively skewed?

post hoc test

- statistical procedure computed following a significant ANOVA to determine which pair or pairs of group means significantly differ

one-way between-subjects ANOVA

4 assumptions 1. normality 2. random sampling 3, independence 4. homogeneity of variance sample size must be equal in each group

F statistic of F obtained

= MSBG/MSE = variance between groups/ variance within groups

Fobt

= variance between groups/variance within groups k-1/N-k

ANOVA

An analysis of variance

independent

If two categorical variables are _______________, they are NOT related or correlated

dependent

If two categorical variables are ________________, they are related or correlated

Df

The chi-square test for Independence = (K1- 1)(K1- 1) = (rows -1)(columns - 1)

ANOVA

The type used to analyze data depends on: 1. The number of factors being tested 2. How the participants are observed across each level of a factor

N-1

What is the df for a one-way between-subject ANOVA?

K>2

When are post hoc tests necessary because multiple comparisons are needed?

post hoc tests

When the ANOVA is significant conduct ___________________________ to determine which pair or pairs of group means significantly differ

between-subjects design

a research design in which we select independent samples, meaning that different participants are observed at each level of a factor each participant participates in one and only one group. The results from each group are then compared to each other to examine differences, and thus, effect of the IV. For example, in a study examining the effect of Bayer aspirin vs Tylenol on headaches, we can have 2 groups (those getting Bayer and those getting Tylenol). Participants get either Bayer OR Tylenol, but they do NOT get both

ANOVA

also called the F test, is a statistical procedure used to test hypotheses for one or more factors concerning the variance among two or more group means, where the variance in one or more populations is unknown

Within-subjects design

an experimental design in which the independent variable is manipulated within subjects (as opposed to between groups) The same group of participants are used in each treatment/survey/etc. For example, a group of 20 students first takes a test with upbeat music and later takes a test with slow music.

2

any variation that can be measured in a study. In the one-way between-subjects ANOVA, there are _____ sources of variation

dfbg or dfnum

associated with the variance for the group means in the numerator of the test statistic. It is equal to the number of groups (k) minus 1

dfbg

degrees of freedom between groups

dfe

degrees of freedom error, degrees of freedom within groups or degrees of freedom denominator

dfnum

degrees of freedom numerator

nonparametric tests

hypothesis tests that are used (1) to test hypotheses that do not make inferences about parameters in a population, (2) to test hypotheses about data that can have any type of distribution, and (3) to analyze data on a nominal or ordinal scale of measurement

f distribution

is derived from a sampling distribution of F ratios

fe

is the expected frequency. This is calculated based on the expected proportion for each category. For goodness of fit, this would be based on the predicted proportions. For independence we will use a separate formula.

one-way between subjects ANOVA

is the most basic type of ANOVA in this type of ANOVA, different participants are observed at each level of one factor

fo

is the observed frequency. This is the actual data that is found within the experiment

k

number of groups

N

number of total participants in a study

n

numbers of participants per group

one-way ANOVA

one factor is tested

null hypothesis

one-way between-subjects ANOVA group means do not vary in the population

alternative hypothesis

one-way between-subjects ANOVA group means in the population do vary

fe

row total x column total /N

chi-square test for independence

statistical procedure used to determine whether frequencies observed at the combination of levels of two categorical variables are similar to frequencies expected -Attempting to determine the extent to which two variables are related -Two categorical variables with any number of levels

chi-square test

statistical procedure used to test hypotheses about the discrepancy between the observed and expected frequencies in two or more nominal categories

dfe

the df associated with the error variance in the denominator. it is equal to the total sample size (N) minus the number of groups (k)

F statistic or F obtained

the test statistic for the ANOVA it is computed as mean square (or variance) between groups divided by the mean square (or variance) within groups

two-way ANOVA

two factors are tested (and so on)

between groups variation

variance of group means

within groups (error) variation

variation attributed to error