PSY 302 Midterm II Prep
For which of the following tests does the calculation of the t-statistic require a pooled standard deviation measure? -one sample z-test -one sample t-test -paired samples t-test -independent samples t-test
independent samples t-test
In a one-way, repeated-measures ANOVA, the degrees of freedom associated with the remaining variability (after variance due to individual differences and the independent variable are factored out )are called _____. -dfTreatment -dfTotal -dfSubjects -dfResidual
dfResidual
A researcher sampled 83 students and plans to run a one sample t-test. Calculate the degrees of freedom for a one-tailed test with an alpha level of .05.
82
Candice is conducting a 2 × 3 ANOVA on the relationship between age (young, old) and smoking status (smoker, nonsmoker, and former smoker) on physical symptoms. What are the degrees of freedom for the effect of age?
1
A researcher sampled 25 people who volunteered to pick up trash on the beach. The volunteers filled out a personality survey, and the researcher hypothesized that the volunteers would score higher on the trait agreeableness than the general population. The mean for agreeableness in the general population is considered to be 3, while the sample of volunteers scored a 4.23 (SD = 1.21). Calculate the estimated standard error of the mean. Round your answer to two decimal places.
0.242
Which of these observed values are more likely to lead to rejecting of the null hypothesis? Select all that apply. 1.) A very small p-value 2.) A large F-value 3.) A large p-value 4.) A small F-value
1, 2
A typical U.S. adult gets 6.8 hours of sleep per night. A sleep researcher tested if college students sleep less than the general population. He asked 24 college students how much sleep they got the night before (in hours) and found that on average they slept 6.3 hours. The researcher is running a one-sample, one-tailed t-test to test his hypothesis. How many degrees of freedom are there for this test?
23 (with margin 0)
When do we need to conduct post-hoc tests after running a factorial ANOVA? -If we find a significant main effect of a factor that has three or more levels -If we find any significant effects. -We never run post-hoc tests in factorial ANOVA -If we find a significant main effect of a factor that has two levels
If we find a significant main effect of a factor that has three or more levels
A researcher conducted a single-sample t-test and found t(23) = 2.24. The critical t-value for a one-tailed, one-sample t-test with an alpha level of .05 and 23 degrees of freedom is 1.71. What is the conclusion? -Reject the alternative hypothesis -We don't have enough information to know whether to retain or reject the null. -Reject the null hypothesis -Retain the null hypothesis
Reject the null hypothesis
In an independent samples t-test, t-values can be positive or negative depending on -the t-statistic is always positive. -which group mean is subtracted from the other in the t-statistic formula. -how large the effect size is. -how large the difference between means is.
which group mean is subtracted from the other in the t-statistic formula.
Compute sum of squares (SS) for the following sample data: 4, 1, 4, 7, 8 Round to two decimal points
30.8
A 3 X 2 factorial design will have ______ different cell means.
6
A waiter wants to know whether it is true that leaving a small chocolate with the bill will increase tips and whether the chocolate has a different influence on men than it does on women. If the waiter asked me to design an experiment to test this, what type of statistical test will I be planning on performing? -independent samples t-test -repeated-measures ANOVA -factorial ANOVA -paired t-test -one-way, between subjects ANOVA -z-test
factorial ANOVA
You should use a one-way repeated measures ANOVA when -testing for significant differences between groups when the same participants are in each group -testing for significant differences between groups when different participants are used in each group -we have exactly one measurement per participant
testing for significant differences between groups when the same participants are in each group
A researcher tested the effect of self-esteem (high, medium, low) and a field of study (psychology, biology, chemistry, mathematics) on the first salary after college. What are the degrees of freedom for the interaction?
6
A one-way ANOVA is used to test for mean differences between/among ________________________________. -one sample and the population -2 or more groups -2 groups
2 or more groups
David conducts a study to look at the effects of stress and social support on physical symptoms. If stress is categorized into low, medium, and high, and social support is categorized into low and high, then the two-way ANOVA design for the study is... -1 x 6 -2 x 3. -2 x 5. -1 x 5 -1 x 1. -2 x 2.
2 x 3
For a paired samples t-test (one-sided), the alternative hypothesis could be which of the following? Select all that apply. 1.) H 1 : μ D ≥ 0 2.) H 1H 1: μ D > 0μ D > 0 3.) H 1H 1: μ D < 0μ D < 0 4.) H 1H 1: μ D ≠ 0μ D ≠ 0
2, 3
A researcher sampled 31 people who volunteered to pick up trash on the beach. The volunteers filled out a personality survey, and the researcher hypothesized that the volunteers would score higher on the trait agreeableness than the general population. The mean for agreeableness in the general population is considered to be 3, while the sample of volunteers scored a 4.04 (SD = 1.95). Calculate the t-statistic for a one sample t-test. Round your answer to two decimal places.
2.97
A clinician is interested in seeing if her patients have lower depression scores after therapy compared to before therapy. For each of her 27 patients, the clinician subtracts the depression score at time two from the depression score at time one. She finds that the mean of the difference scores is -0.08 (SD = 1). She runs a paired samples t-test with how many degrees of freedom?
26 margin of error +/- 0.01
With a sample of 30, the degrees of freedom for a one-sample t-test would be -28 -29 -31 -30
29
In a one-way, between-subjects ANOVA with 4 groups and 6 people in each group, what is the degrees of freedom between?
3
When conducting a two-way ANOVA, how many decision rules must be established? ~2 ~4 ~3 ~1
3
A study comparing men and women on empathy reported t(22) = 1.92, p>0.05. What can we conclude? Select all that apply 1.) The alternative hypothesis is true 2.) The sample size was 22 3.) The null hypothesis was retained 4.) The results are not statistically significant 5.) The null hypothesis was rejected 6.) The results are statistically significant
3, 4
In order to calculate the standard error of the difference scores for a paired samples t-test, you need to know 1.) The standard deviation of the populations for each variable. 2.) The standard deviation for each time the variable is measured. 3.) The standard deviation of the difference scores. 4.) The sample size.
3, 4
In a one-way, between-subjects ANOVA with k = 6 groups and n= 11 participants in each group, what is the degrees of freedom within?
60
Given that the sum of squares between = 9 and the sum of squares total is = 99, what is the sum of squares within?
90 margin of error +/- 0.5
The most commonly used measure of effect size for an independent samples t-test is -p-value -t-value -Cohen's d -degrees of freedom
Cohen's d
The most commonly used measure of effect size for independent samples t-test is -t-value -p-value -Cohen's d -eta squared
Cohen's d
Which case will lead to the largest value for an F-statistic? _________ variability among sample means and _________ variability within each sample. -Large; small -Small; small -Small; large -Large; large
Large; small
The degrees of freedom for a paired samples t-test is -(n1 + n2) - 2 -(N / 2) - 1 -N - 1 -N - 2
N - 1
The formula for calculating the degrees of freedom for an independent samples t-test is -N -N - 1 -N - 2 -(n1 + n2) - 1
N - 2
What is the null hypothesis for an independent samples t-test? -One sample mean is greater than the other sample mean -The two independent samples are drawn from populations with the same mean. -The two independent sample means are different from each other. -The two independent samples are drawn from populations with different means.
The two independent samples are drawn from populations with the same mean.
Under what circumstance does the t-distribution look nearly identical to the z-distribution? -When the sample size (N) is very large. -The distributions are always identical. -When the mean of the distribution is zero. -When the standard deviation of the sample is very small.
When the sample size (N) is very large.
Bonferroni, Holm, Tukey are all examples of -inference tests -statistical distribution -ANOVA terminology for variability -corrections for multiple comparisons
corrections for multiple comparison
In a one-way, repeated-measures ANOVA, the degrees of freedom associated with variability due to the independent variable are called _____. -dfTreatment -dfResidual -dfSubjects -dfTotal
dfTreatment
Two-way ANOVA is also known as..... -paired ANOVA -one-way ANOVA -repeated measures ANOVA -factorial ANOVA
factorial ANOVA
A statistics professor is interested in the effect of electronic textbooks on learning. She assigns one of her sections of introductory statistics to use a traditional textbook and the other section an equivalent electronic textbook. One question the professor might ask is whether the choice of textbooks had an effect on exam performance. Which statistical test would be the most appropriate choice to investigate this question? -repeated-measures ANOVA -paired t-test -factorial ANOVA -independent-samples t-test
independent-samples t-test
In a one-way, repeated-measures ANOVA, which equation is used to calculate dfSubjects? -dfSubjects × dfTreatment -n - 1 -N - 1 -k - 1
n - 1
In a one-way ANOVA, the factor is most commonly on which type of scale? -interval -nominal/categorical -ratio -ordinal
nomical/categorical
In a one-way ANOVA, the outcome variable must be..... -ordinal -on interval or ratio scale -categorical/nominal
on interval or ratio scale
A paired samples t-test is essentially a(n) -one sample z-test for difference scores -a between subjects analysis of variance -independent samples t-test -one sample t-test for difference scores
one sample t-test for difference scores
Eta squared is an effect size that refers to the proportion of variability in the outcome variable that can be explained by the __________________. -mean squared between -predictor -mean squared within -covariates
predictor
Larger F-values indicate that ... Select all that apply. 1.) there is greater variability between groups than within groups 2.) group mean differences are larger than what would be expected by chance 3.) group 1 has greater variance than group 2 4.) there is greater variability within groups than between groups 5.) the observed data are unlikely if the null hypothesis was true
1, 2, 5
If the null is false (i.e., if there is a true effect in the population), what will happen in a statistical test of that effect if you increase the sample size? Select all that apply 1.) effect size remains relatively unchanged 2.) standard error remains relatively unchanged 3.) standard error becomes smaller 4.) p-value remains relatively unchanged 5.) effect size becomes larger 6.) standard error becomes larger 7.) p-value becomes smaller 8.) sample means become larger 9.) p-value becomes larger
1, 3, 7
When will the independent samples t-value be more likely significant? 1.) When the differences between sample means are large 2.)When the differences between sample means are small 3.) When there is a large variability in each group 4.) When there is a small variability within each group
1, 4
A researcher tests the working memory capacity of 18 world class poker players and plans to run a one-sample t-test to determine if poker players have a higher working memory capacity than the general population (μ = 7). The participants in the study remembered on average 8.19 words from the word list (SD = 2.94). Calculate the t-statistic. Round your answer to two decimal places.
1.72
Given: The total number of participants = 135 Number of groups = 3 SSb = 14 SSw = 242 What is the mean squares within? Round to two decimal points
1.83
Given: Number of participants = 105 Number of groups = 7 SSb = 68 SSw = 222 What is the value of mean squares between? Round to two decimal points
11.33
Compute variance (MS) for the following sample data: 2, 7, 9, 1, 1 Hint: Make sure to use n-1. Round to two decimal points
14 margin of error +/- 0.2
Jeremiah is conducting a 2 × 3 ANOVA on the relationship between athletic status (athlete, nonathlete) and socioeconomic status (low SES, mid SES, and high SES) on physical symptoms. What are the degrees of freedom for the effect of socioeconomic status?
2
Based on the following output from an independent samples t-test, t(21) = 1.34, p >.05, CI = [-5.34, 14.30], what can you conclude? Select all that apply. 1.) Reject the null hypothesis. 2.) There is not enough evidence that the samples were drawn from populations with different means. 3.) Fail to reject the null hypothesis 4.) The samples were drawn from populations with different means.
2, 3
For which of the following would a paired t-test be appropriate? Select all that apply. 1.) A researcher is studying differences in personality traits between left-handed and right-handed people. 2.) A researcher is looking at the relationship between agreeableness and extraversion on the same individuals. 3.) A researcher is comparing performance before and after a training program. 4.) A researcher is studying neuroticism in parent-child dyads.
2, 3, 4
When p-value is _________, we will retain the _________ hypothesis. -above 0.05; alternative -above 0.05; null -below 0.05; null -below 0.05; alternative
above 0.05; null
One way to think about the F-value in ANOVA is as a ratio comparing variability due to treatment+variability due to error. The variability due to treatment+error in this calculation refers to the... -mean differences between groups -between group variance -individual differences within groups -within group variance
between group variance
A researcher is running a one-sample, two-tailed t-test with an alpha level of .05. As the number of participants she collects increases, the critical t-value -decreases. -there is not enough information to answer this question. -stays the same. -increases.
decreases
What statistical test should be used to compare psychology knowledge of students who are psychology majors with those who are not? -one-sample t-test -one-way ANOVA -independent-samples t-test -paired t-test
independent-samples t-test
The MS within is sometimes referred to as the error variance. A key source of error variance is ... -treatment effect -individual differences -degrees of freedom -different levels of the factor
individual differences
In a clinical trial, a third of participants are assigned into the psychotherapy treatment group, one third into the psychotherapy + medication group and one third into a control (no treatment) group. Which test should be used to compare the degree of depressive symptoms between groups at the conclusion of the trial? -independent samples t-test -paired t-test -repeated-measures ANOVA -one-way ANOVA
one-way ANOVA
A one-way repeated measures ANOVA is used for experimental designs that collect data from... -different participants in each condition -one person during a single lab visit -at least three groups -the same participants in each condition
the same participants in each condition
