Characteristics
The characteristics of a dependent variable of a One way ANOVA.
What is a continuous dependent variable that approaches at least interval level?
The equations used to get the degrees of freedom.
What is
dfBetween = k - 1
dfWithin = Ntotal - K
Null Hypothesis (H0).
What is no difference in the population means?
The goal of Post Hoc tests.
What is determining which pairs of population means are different from one another while holding the risk of a type 1 error to a set alpha level?
Colgate PBSC is running a study to see if their undergraduate students perform higher on average on Quantitative research methods exams than the national average of undergraduate psychology majors.
One sample T-test
This is the number of independent variables in a One-Way ANOVA.
What is one independent variable?
The notation for reporting F-statistic at alpha level .05.
What is F.05=(dfBetween, dfWithin)?
Alternative Hypothesis (H1).
What is at least one population mean differs from the others?
(By default, ANOVA is non-directional)
Tukey's HSD.
What post hoc test allows us to test the null that each pair of population means are the same to help us discover which conditions are likely to differ in the population?
A researcher is conducting a study where they are trying to determine if watching a pre lecture video helps improve exam scores. Participants are randomly assigned to ether watch recorded pre lecture videos or watch a short video of puppies
What is an independent means T-test
The number of levels or factors that are associated with the independent variable of a One way ANOVA.
What are 3 or more levels?
(While an ANOVA can be conducted for an IV with 2 levels, typically a t-test would be utilized)
The F - ratio.
What is the ratio that utilizes variance between groups compared to within groups to see if the mean of groups differs significantly?
The equation for the test statistic.
F= Mean Squares Between / Mean Squares Within
The effect size for the overall analysis.
What is Eta Squared?
η2= SSEffect/ SSTotal
A researcher is conducting a study where participants are trying to see how many cup flips they can get in a minute. Participants first compete the task while being watched by a group (3 people) then complete the same task again while not being watched at all.
What is an dependent means T-Test?
What is testing if the variation between groups exceeds the variation within groups?
Characteristics of the F-Distribution.
What is described by the curve is anchored at 0 and peaks at 1 with large values skewed out in the tails?
The APA style write up for:
dfBetween=2, MSBetween=11.26
dfWithin=15, MSWithin=1.16, at alpha level .05
What is
Based on the sample data, we reject the null hypothesis. The levels of the independent variable does significantly affect the dependent variable, as there is at least one significant difference among the 3 groups, F(2,15)=9.71, p<.05.
A measure of effect size when there are more than 2 means.
What is Eta-squared?
A researcher is interested in studying if having ice cream the night before an exam increases performance. Participants are randomly assigned to either eat a bowl of ice cream the night before an exam or to not have ice cream.
What is an independent means t-test?
The reason for running an ANOVA rather than multiple T-tests.
What is to reduce the type 1 error rate?
(Every test has error associated with it therefore the more tests you run, the more error there is.)
True or False: if you calculate an F-statistic that is >1 your results are significant and you can automatically reject the null hypothesis?
False!
The calculated F statistic must still be compared to a critical value at a set alpha level. Simply having an F statistics >1 does not automatically indicate statistical significance, it only indicates that there is more variability in the numerator than the denominator, we still must account for error.
True or False: after calculating the F-statistic and find that there is a significant difference between conditions, you can reject the null hypothesis, you are done and can report your findings?
False!
Following this you must complete post hoc tests
True or False: Eta-squared represents the proportion of the variability in the dependent variable is associated with the effect of the independent variable
True!
A researcher is conducting a study on the effect of an audience on an individuals performance on a task where they must make as many baskets as they can in 5 minutes.
Participants are randomly assigned to be in one of 3 conditions: alone/ no audience, one person watching them, or 5 people watching them.
What is a One Way ANOVA