research lecture 6 Flashcards by sophia carrasco

if it’s a two-tail test….you interpret the p
value in SPSS using ___. SPSS is adjusting it for
you (dividing it in half)

.05

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if you need to adjust the alpha
further…ex/ Bonferroni adjustment for 2 t-
tests….then compare the SPSS p-value to ___
to determine significance.

.025

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what is the difference between T-test and ANOVA

T-test: compares 2 means and only has one IV
ANOVA: compares 3+ means and only used when u have more then 1 IV

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can you use a T- Test from a one way repeated measures

yes bc only 1 IV

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can you use a T-test from a posttest only randomized group and posttest only non randomized

yes

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if we want to compare several means why don’t we
compare multiple pairs of means with t-tests?

inflates the type 1 error rate

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like a t-test, ANOVA tests the ____ hypothesis that the means are approximately the same.

null

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what does a experimental hypothesis mean for an ANOVA

the means differ between each other

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ANOVA is an ____ test

Omnibus

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ANOVA is an Omnibus test .. what does it test, tell us and doesn’t tell us

-It tests for an overall difference.
– It tells us that the means are different.
– It doesn’t tell us exactly which means differ.

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what is An “overall test“ - tests a number of different comparisons at once

omnibus

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what does an 2x3x4 ANOVA tell us

3 IV

on has 2 variables
one has 3 variables
one has 4 variables

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what ANOVA is it called if there is 2 or more IV ar least one is independent and one is repeated

2+x2+ mixed or split plot ANOVA

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how do u find the mean squares

sum of squares / degree of freedoms

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how many DF is there for an ANOVA

these are always 2 .. one has to do with the amount of groups minus 1 and other one has to do with the number of ppl

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can the F result from the omnibus ANOVA tell us if it is significant

no not by itself

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a significant omnibus (global) test tells us that there is a difference among the ___ or the group ___ are different somewhere

means 2x

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what does a significant omnibus does not tell us

specifically which group means different from which

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do you use follow up test with a significant omnibus test

yes always

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how do you do follow up test for an omnibus test?

planned contrasts or post HOC comparisons

do not use multiple t test

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is a planned contrasts or Post HOC comparisons get significance easier ?

planned

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what is a planned contracts

planned prior
ex: u only want to compare
the placebo group to each tx.
group.

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what is a post HOC comparisons

not planned (no hypothesis)
compares all paris of means

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when do u use a post hoc

any stat test after global omnibus ANOVA (usually has 2 means)

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what do u run after global (omnibus test) and have significant interaction

simple effects

when do u do a pairwise

usually after global test (only 2 means)

what are the post hoc statistical test designed to control

the alpha level ( basically control the family wise (overall) error rate)

what are the 3 most common post hoc test

- bonferroni -turkey -games-howell

what post hoc test do.u use when there are only small deviation form normality , sample sizes in each cell are equal and the variances are homogeneous

-bonferroni -turkey

what post hoc test do u use if variances are not homogenous

games-howell

bonferroni and turkey are conservative and controls type __ error when is each more powerful

1 bonferroni is more power if the number of comparisons are small and turkey is more power if the number of comparisons are large

what part in the research do u include the significance difference in

the results

what is the non-parametric equivalent to an independent one-way ANOVA.

kruskal - wallis test

when do u select the kruskal walllis test

when data doesn’t meet assumptions

what does kruskal wallis test compare

compares mean ranks among the groups

what are the follow up test for the kruskal wallis test

mann - whitney u test ( non-parametric equivalents to independent t-tests)

for a repeated measures one way anova what do u test first and then what do u follow up with

perform a global or omnibus test first (is there a difference somewhere) and then follow up with bonferroni post hoc comparisons

what is the assumptions that the variances of the differences between all possible pairs of groups (ex/ levels of the repeated IV) are equal.

sphericity

what is the test for the assumption of sphericity called

the manuchleys test

do you want the Manuchley’s test to be significant or not

what values are used in a RM one way ANOVA if the assumptions (sphericity) is violated

EPsilon - greenhouse -hunyhn feldt - lower bound

if your sig is .188 on a RM one way anova is sphericity violated or not

no it has not been violated bc p > .05 it is only violated if the sig is < .05

what does the 1St Degree of freedom for an anova represent

related to the # of groups - one

what does the 2nd Degree of freedom for an anova represent

the # of participants per group

what is the non parametric equivalent to a RM – one-way ANOVA

freiedmans ANOVA

when runngin a friedman ANOVA, In SPSS this will give you the global result (is there a difference somewhere)…and all pair-wise comparisons are analyzed using ____ ___ __

Wilcoxon Signed Ranks.

what is a two way independent anova

two + IV

in a 2 way independent anova there are different participants in what condtions

all

if there is more than one IV what is it called

a factorial design or a factorial anova analysis

what is a benefit of a factorial deigns

we can look at how variables interact

what do the interactions of the factorial design tell us

the effect of one IV depends on the vaule of another IV

the first analysis of the ANOVA consists of ___ test

what is included in the omnibus or global ANOVA

interaction main effect for one IV test main effect for second IV

if the ___ is significant u don’t have to worry about the main effect

interaction

on a graph when will the interaction not be significant

when they are parallel to each other

when do u run simple effects

run after global and significant interaction

if you run a global anova (interaction and main effects) and the main effect(s) and the interaction is not significant what do u do

run follow up main effect pairwis comparisons (post HOC comparison and adjust the alpha levle

if there is only 2 levels for the main effect do u do a follow up test

if you run a global anova (interaction and main effects) and the main effects are significant and the interaction is significant what do u run after

run simple effects and “forget: about the main effects and adjust the alpha level

when do u run simple effects

only run if u have a significant interaction

when u run simple effects can u adjust ur alpha ?

yes ofc

you can only look for difference inside the ANOVA cells if what

u have a significant interaction

•You can ONLY look for differences inside the ANOVA cells IF you have a significant interaction. Otherwise you are forced to ONLY report the what

outcome of the main effects .. the main effect post hoc test if more then 2 levels

if u have to many levels from ur anova what happens to the alpha

it get smaller

to test for differences between group means when we know that an extraneous/confounding variable can affect the ____ variable.

outcome

if u can identify the covariate and measure it what does that do to your analysis

strengthens it and more likely to find significance

First, we use SPSS to determine if compliance really did affect the pain scores…if yes….we use SPSS to adjust the means to take this into account….so the difference isprimarily based on the intervention and not compliance.. any time an ANOVA is done this way what is it called

ANCOVA ,,, an analysis of covariance

when we want to test for difference between groups when we have several DV’s what do we run

MANOVA

why is running a MANOVA when testing for difference between groups when we have several DV’s better then running multiple ANOVAs

-controls family wise error rate (type 1) - takes into account the relationships between the DVs , so more powerful then seperate ANOVAs

what is the next step after a significant global MANOVA

DFA (discriminating function analysis )

what is the discriminant analysis used to determine

which of the groups 4 DV’s are best at discriminating (separating) the groups