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Calculation
Conceptual
Statistical Sentence
Grab Bag?
100
A psychologist would like to examine the effects of sugar consumption on the activity level of preschool children. One group gets no sugar, one group gets a small dose, and the third group gets a large dose. The psychologist records the activity level for each child.
What is a One-Way ANOVA?
100
An analysis of variances produce SSbetween = 30, SSwithin = 60, and an F-ratio with df = 2, 15. For this analysis, what is the F-ratio? a. 6/2 = 3 b. 6/4 = 1.5 c. 6/0.25 = 24 d. 6/0.50 = 12
What is 3?
100
In an independent-measures hypothesis test, what does t = 0 tell us about the the sample means?
The two sample means must be equal.
100
The results of a independent samples t-test are reported as follows: t(29) = 2.70, p = .04. Based on this report, how many individuals were in the sample AND should you accept or reject the null?
N=31 AND reject the null
100
A sample of n = 25 individuals is selected from a population with µ = 80, and a treatment is administered to the sample. Which set of sample characteristics is most likely to lead to a decision that there is a significant treatment effect? a. M = 85 and large sample variance b. M = 85 and small sample variance c. M = 90 and large sample variance d. M = 90 and small sample variance
What is M=90 and small sample variance?
200
A researcher would like to examine how the chemical tryptophan, contained in foods such as turkey, can affect mental alertness. A sample of n = 9 college students is obtained and each student’s performance on a familiar video game is measured before and after eating a traditional Thanksgiving dinner including roast turkey. The average score dropped by M = 14 points after the meal with SS = 1152 for the difference scores.
What is repeated measures t-test?
200
One sample has n = 8 and SS = 21 and a second sample has n = 8 and SS = 35. What is the pooled variance for the two samples?
What is 56/14 = 4?
200
For the independent-measures t statistic, what is the effect of increasing the sample sizes on likelihood of rejecting the null?
As sample size increases, likelihood of rejecting the null increases.
200
What are the critical t values that form the boundaries of the rejection region for a two-tailed test using a sample of n = 9 scores and an alpha level of .05?
±2.306
200
Which of the following is the correct null hypothesis for a repeated-measures t test? a. MD = 0 b. µ1 = µ2 c. M1 = M2 d. µD = 0
What is µD = 0?
300
A researcher is interested in testing the itching side effect some people reported when using new Hairy Brand Hairspray. In the general population people scratch their head approximately 2 times per hour. The researcher asks a group of women to use the new hairspray, and then records how often each woman scratches her head in an hour.
What is a One-Sample t-test
300
A repeated-measures t-test produces a sample mean difference of MD = 4.5 with s2 = 100 for a sample of n = 16 participants. For this study, the estimated value of Cohen’s d would be ____.
Cohend's d = 4.5/10 = 0.45
300
As sample variance increases, explain what happens to the likelihood of rejecting the null hypothesis AND what happens to measures of effect size such as Cohen's d?
Likelihood decreases, AND measures of effect size decrease.
300
For the main effect on a One-Way ANOVA, the following. How many people were in the study AND what can you conclude? F(3,68) = 2.65, p >.05
N=72 AND accept the null
300
For an experiment comparing more than two treatment conditions, why should you use an ANOVA rather than separate t tests?
Since you will increase your chance of making a Type I error. Alpha will increase. Best to use as few tests as possible.
400
A psychologist examines long term retention of a learned task in a sample of n = 6 rats. At 90 days of age, rats are trained on a discrimination task. Their initial performance is recorded to serve as a baseline for subsequent comparisons. Then their performance is tested four more times at 6 months, 1 year, 1 1/2 years, and 2 years of age.
What is Repeated Measures ANOVA?
400
An analysis of variances produce SSbetween = 30, SSwithin = 60, and an F-ratio with df = 2, 15. For this analysis, what is the F-ratio?
What is 15/4 = 3.75?
400
Explain 1 positive aspect of a repeated measures design, AND 1 negative aspect
Study change overtime (developmental), fewer participants needed, removes the effect of individual differences, easier to get significant results. Lose participants, "order effects", other factors (historical events, etc.) may influence people between session 1 and session 2.
400
For a repeated measures ANOVA, how many sessions are in the study AND should we accept or reject the null? F(3,5) = 3.65, p=.002
k=4 AND reject the null
400
A two-way ANOVA has a significant interaction of Gender and Marital Status on measures of Happiness. Married women M= 8, Married men M= 15, Single men=6, Single women = 13. Draw the graph using the following information, and use this to help you explain the interaction in words. Male
Women tend to be happier when they are single rather than married. Men tend to be happier when they are married rather than single.