Chapter 12 Flashcards
Formula for variance
Sd squared
What is ANOVA used for
examine differences in sample means amoung 3 or more groups
ANOVA tests the relationship significance between
an independent variable with at least 3 categories (of nominal or ordinal display) and a dependent variable (of interval-ration display)
ANOVA question
are the differences between the sample large enough to reject the null hypothesis
State the null hypothesis for ANOVA
H0: U1=U2-U3…
If the null hypothesis for ANOVA is true
the sample mean should be close to the same value
If the null hypothesis is false
there should be a huge difference in sample means
What is the ANOVA test statistic called
F ratio
What does the F ratio represent
Estimate of the amount of variation between
categories of the independent variable
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Estimate of the amount of variation within each of the categories of the independent variable
SST and what it means
total sum of squares
the grand mean
SSW
Sum of squares within
SSB
sum of squares between
SST
total variation of the scores
Why do we standardize the cases and how
because the number of cases may not be equal
It’s done by dividing SSW and SSB by their corresponding degrees of freedom
What does a high F ratio mean
we are more likely to reject the null hypothesis
Step 1 for ANOVA (4)
-independent random sample
-Interval-Ratio dependent variable
-population normally distributed
-population variances are equal
State H1
at least one of the sections has a different mean score in the population
What tail is ANOVA
one-tailed test
DFW on F-score
Look up and down
DFB on F-score
look back and forth
When does the test statistic of an ANOVA not fall in the critical range
when the F (obtained) is smaller then the F (critical)
When do we fail to reject the null hypothesis (accept it)
when the test statistic doesn’t fall into the critical region
x̄= for ANOVA
grand mean
What does the H1 not explain
Doesn’t say which part or how many are different
What is eta squared similar to and what is the symbol
like Cohen’s d
N squared
What does Eta squared explain
It’s a measure of effect size (a value of 0.06 is a small effect and means it is not statistically significant)
What is a post-hoc test examine
which categories are significantly different from each other
