Ch.12 stats
An analysis of variance is used to evaluate the mean differences for a research study comparing 4 treatment conditions and 7 scores in each sample. How many total degrees of freedom are there?
27
In an ANOVA study on the impact that various forms of cellphone use have on driving speed, a researcher concludes that there are no systematic treatment effects. What was the F-ratio closest to?
1
A researcher is conducting an ANOVA test to measure the influence of the time of day on reaction time. Participants are given a reaction test at three different periods throughout the day: 7 a.m., noon, and 5 p.m. In this design, there are _______ factor(s) and ______ level(s).
1,3
A research report concludes that there are significant differences among treatments, with "F(2, 27) = 8.62, p < .01." If the same number of participants was used in all of the treatment conditions, then how many individuals were in each treatment? Select one:
10
An analysis of variance produces SStotal = 80 and SSwithin = 30. For this analysis, what is SSbetween?
50
ANOVA is to be used in a research study using two therapy groups. For each group, scores will be taken before the therapy, right after the therapy, and one year after the therapy. How many different sample means will there be?
6
If an analysis of variance is used for the following data, what would be the effect of changing the value of M1 to 20? Sample Data M1 = 15 M2 = 25 SS1 = 90 SS2 = 70
Decrease SSbetween and decrease the size of the F-ratio.
An analysis of variance is used to evaluate the mean differences for a research study comparing five treatment conditions with a separate sample of n = 6 in each treatment. If SSbetween treaments = 24 and SStotal = 74, find the F-ratio.
F=3
For an independent-measures experiment, the F-ratio is 3.1. If dfbetween = 5, and dfwithin = 14, what will the researcher conclude?
The null hypothesis will be rejected with α = 0.05, but not with α = 0.01
Three different treatments (A, B, and C) are being studied using ANOVA. The means are computed: MA = 9, MB = 4, MC = 6. If MSwithin = 6.21, n = 7, and q = 3.67, which of the following is true using Tukey's HSD test?
Treatment A is significantly different from Treatment B.
A researcher reports an F-ratio with df = 2, 18 from an independent-measures research study. Based on the df values, how many treatments were compared in the study and what was the total number of subjects participating in the study?
3 treatments and 21 subjects
An analysis of variance produced an F-ratio with df values 14, 1. If the same data had been evaluated with an independent-measures t test, what would be df?
14
If the variance between treatments increases and the variance within treatments decreases, what will happen to the F-ratios and the likelihood of rejecting the null hypothesis in an ANOVA test?
The F-ratio and the likelihood of rejecting the null hypothesis will increase.
An analysis of variance produces SSbetween = 30, SSwithin = 60, and an F-ratio with df = 2, 15. For this analysis, what is the F-ratio?
15/4 = 3.75
The following table shows the results of an analysis of variance comparing four treatment conditions with a sample of n = 5 participants in each treatment. Note that several values are missing in the table. What is the missing value for the F-ratio? Source SS df MS Between 30 xx xx F = xx Within xx xx xx Total 62 xx
5.00
For a posttest following ANOVA, there are four different treatment groups. How many pairwise comparisons must be made to gain a complete understanding of which treatment effects differ significantly from others?
6
If SSbetween = 125 and SSwithin = 65, what is the effect size, η2, for the corresponding ANOVA?
66%
A research report concludes that there are significant differences among treatments, with "F(3,28) = 5.62, p < .01, η2 = 0.28." If the same number of participants was used in all of the treatment conditions, then how many individuals were in each treatment?
8
An analysis of variance comparing three treatment conditions produces dfwithin = 21. If the samples are all the same size, how many individuals are in each sample?
8
An analysis of variance produces SS between = 64 and MS between = 8. In this analysis, how many treatment conditions are being compared?
9
What is stated by the alternative hypothesis (H1) for an ANOVA?
At least one of the population means is different from another mean.
Which of the following most accurately describes the F-ratio in ANOVA testing?
The ratio of variances
Under what conditions might a post hoc test be performed following ANOVA?
When there are three treatments and the null hypothesis was rejected.
Which of the following will increase the likelihood of rejecting the null hypothesis using ANOVA?
a. A decrease of SSwithin b. An increase in the sample sizes
In an analysis of variance, the primary effect of large mean differences within each sample is to increase the value for ______.
the variance within treatments
What is the main advantage that ANOVA testing has compared with t testing?
It can be used to compare two or more treatments.
If an analysis of variance is used for the following data, what would be the effect of changing the value of SS1 to 50? Sample Data M1 = 10 M2 = 15 SS1 = 90 SS2 = 70
Decrease SSwithin and increase the size of the F-ratio.
In an analysis of variance, which statement is false?
MStotal = MSbetween + MSSwithin