Statistics final word questions
Under what circumstances get a very small treatment effect be statistically significant?
If the sample size is large and the sample variance is small
In an analysis of variance, which of the following statements is not true?
MStotal = MSbetween + MSwithin
If a treatment is expected to increase scores on a variable for which the mean is expected to be mu = 100, what is the null hypothesis?
Mu with treatment _< 100
Which situation below violates an assumption for conducting hypothesis tests using the T statistic?
None of these situations violates an assumption for conducting hypothesis tests using the T statistic
Which of the following is not an aspect involved in computing the sum of products (SP) of deviations?
Subtracting the total sum of squares collapsed across all scores
Which of the following is a fundamental difference between a T statistic and a Z score
The T statistic uses the sample variance in place of the population variance
Which of the following best describes the possible values for a chi-square statistic?
The chi-square statistic is always positive but can contain fractions or decimal values.
In ANOVA, what is represented by the T?
The sum of the scores in a specific condition
In ANOVA, what is represented by the letter N?
The total number of scores in the entire research study
The data for chi-square test consists of ________.
frequencies
For the repeated-measures t statistic, df = _____
n - 1
A researcher is using a chi-square test to determine whether people have any preferences among three brands of televisions. The null hypothesis for this test would state that______.
one-third of the population prefers each brand.
Consider that a researcher is examining the relationship between amounts of physical activity and weight among adults. The researcher goes to a local athletics club to sample individuals who frequently exercise to examine the correlation between physical activity and weight. What is the most prominent concern regarding this research study that may obscure the true nature of the relationship between physical activity and weight among the population of adults?
restriction of range
What is the average value expected for the independent-measures t-statistic if the null hypothesis is true?
t = 0
Which of the following results from a hypothesis test involving the computation of a t-statistic is structured correctly based on standards for presenting hypothesis test in scientific reports?
t(19) = 2.30, p < .05, r^2 = 0.42
A researcher assesses work ethic among college students using a self-report questionnaire. Moreover, the researcher tracked how many our students seek out extra support at the tutoring center and with their professors on campus during the semester. The researcher determines that there is a significant positive relationship between self-reported work ethic and the number of hours students seek out extra support at the tutoring center and with their professors during the semester. This demonstrates how correlations can be used to demonstrate _____.
validity.
Which of the following statements is a correct comparison between Scheffe and Tukey post hoc tests?
A Scheffe post hoc test tends to require a greater difference between conditions for statistically significant difference than a Tukey post hoc test.
For the independent-measures t statistic, what is the effect of increasing the sample variances?
A decrease in the likelihood of rejecting H0 and a decrease in measures of effect size
A researcher plans to conduct a research study compared to treat the conditions with a total of 20 participants. Which of the following designs were produced 20 scores in each treatment?
A repeated measures-design
All else constant, which combination of factors with increased the width of a confidence interval most?
A smaller sample size and a larger confidence interval
For the independent-measures t statistic, what is the effect of increasing the difference between the sample means?
An increase in the likelihood of rejecting H0 and an increase in measures of effect size
For an independent-measures t statistic, what is the effect of increasing the number of scores in the samples?
An increase in the likelihood of rejecting H0 and little or no influence on measures of effect size
Which of the following is an accurate distinction between repeated-measures and independent-measures research designs?
And repeated-measures research designs, each participant is measured once on the same variable.
For ANOVA comparing three treatment conditions, what is stated by the alternative hypothesis (H1)?
At least one of the three population means is different from another population mean.
In an analysis of variance, differences between participants contribute to which of the following variances?
Both between-treatments variance and within-treatments variance
Which of the following research situations would be most likely to use an independent-measures design?
Compare the mathematics skills for 9th-grade boys relative to 9th-grade girls
For which of the following situations with repeated measures research design be appropriate?
Comparing pain tolerance with and without acupuncture needles
A researcher conducts a hypothesis test using a sample of N = 20 with M = 34 for an s^2 = 36 from an unknown population. What is the DF value for the t statistic?
DF = 19
Which bit of information is not attainable for the results of a t-test written up in a statistical report?
Each of these bits of information is attainable from the results of a t-test written up in a statistical report
Which of the following elements is always present it last in a statistical report statement describing the results of an independent-measures t test?
Effect size
Which of the following is an accurate comparison between the expected and observe frequencies for a chi-square test?
Expected frequencies can contain fractions to decimals, and observed frequencies are always whole numbers
On average, which value is expected for the F-ratio if the null hypothesis is true?
F = 1
When n is small (less than 30), how does the shape of the t distribution compare to the normal distribution?
It is flatter and more spread out than the normal distribution.
Which of the following statements accurately describes the chi-square test for independence?
It is similar to both correlation and independent measures t-test because it can be used to evaluate relationship between variables or a difference between populations.
If the mean and variance or computed for each sample and an independent-measures, two-factor experiment, which of the following types of sample data will tend to produce large F-ratios for the two factor ANOVA?
Large differences between sample means and small sample variances
How does the sample variance influence the estimated standard error and measures of effect size such as r^2 and Cohens d
Larger sample variance increases the estimated standard error but decreases measures of effect size
In a two factor experiment with two levels factor A and two levels factor factor B, three of the treatment means are essentially identical and one is substantially different from others. Which result(s) would be produced by this pattern of treatment means?
Main effects for both factors A and B, and as well as an interaction between factors A and B.
Which of the following bits of information is referenced first in an APA formatted statistical report of the results regarding a two factor ANOVA?
Means and standard deviation's for all factor conditions
Which of the following describes the effect of an increase in the variance of difference scores in a repeated-measures design?
Measures of effect size and the likelihood of rejecting the null hypothesis both decrease
Which of the following is the correct null hypothesis for independent-measures t-test
Mu1 - Mu 2 = 0
Which of the following is the correct alternative hypothesis for an independent-measures t-test?
Mu1 - Mu2 =/= 0
Which of the following is consistent with null hypothesis regarding the main effect factor factor A, which is comprised of two levels?
MuA1 = MuA2
Which of the following is consistent with the alternative hypothesis regarding the main effect of factor B, which is comprised of two levels?
MuB1 =/= MuB2
Which of the following bits of information is referenced last in an APA format at statistical report of the results regarding two factor ANOVA?
Partial eta squared as a measure of effect size
Which bit of information needs to be included in a statistical statement that adheres to APA formatting when reporting the results of a chi-square test that is not included in the statistical statement for other types of statistical tests?
Sample size (n)
For a group of graduating college seniors, a researcher records each students rank in his/her high school graduating class and the students rank in the college graduating class. Which correlation should be used to measure the relationship between these two variables?
Spearman correlation
Which statement below is consistent conceptually with what a computed Pearson's r value represents?
The Pearson's R-value represents the degree to which X and Y scores covary together relative to how much X and Y scores vary separately.
Assuming all other factors are held constant, if the DF value for two-tailed T test with a = .05 were increased from DF = 6 to DF = 20, what would happen to the critical values for T?
The critical values would move closer to t = 0
The null hypothesis for a repeated-measures test states which of the following?
The entire population will have a mean difference of MuD = 0
What is referred to by the term expected frequencies?
The frequencies computed from the null hypothesis
What is referred to by the term observed frequencies?
The frequencies found in the sample data classified into each category
Which of the following is consistent with the alternative hypothesis for the interaction of factors A and B in a two-factor analysis of variance?
The main differences between treatment conditions are not what would be predicted from the overall main effects of factors A and B.
Which of the following is not an assumption of the two factor ANOVA?
The observations within each sample must have equal variances.
Which of the following is consistent with what r^2 represents as a measure of effect size?
The portion of variability in a sample attributable to a treatment effect after correcting for sample size
The results of a hypothesis test are reported as follows in a scientific report: t(17) = +2.76, p< .05. Based on this information, which statement below is not correct?
The probability that there is a statistically significant effect less than 5%
If a researcher is using a T statistic to test a null hypothesis about a population what information is needed from the population to calculate the T statistic
The researcher does not need to know any information about the population
A researcher obtained the negative value for the chi-square statistic in a chi square goodness of fit test. What can a researcher conclude based on this result?
The researcher made a mistake because a Chi-square value cannot be negative
Which of the following statements is not consistent with the assumptions necessary when computing a related measures t statistic?
The scores between each treatment must be independent.
Which of the following is not an assumption underlying the independent-measures t formula for hypothesis testing?
The two samples must have equal sample sizes
For ANOVA comparing three treatment conditions, what is stated by the null hypothesis (H0)?
There are no differences between any of the population means.
Crossing, non-parallel lines in a graph pertaining to separate factors (i.e., A & B) in a two-factor analysis a variance indicate which of the following?
There is an interaction between factors A and B.
Which of the following describes the effect of increasing sample size and repeated-measures design?
There is little or no effect on measures of effect size, but the likelihood of rejecting the null hypothesis increases.
A researcher conducts a research study to examine whether there is a difference between two treatments regarding anxiety. Which of the following is consistent conceptually with the null hypothesis?
There is no difference between the two treatments among the general population regarding anxiety.
Two parallel lines in a graph pertain to separate factors(i.e., A & B) in a two-factor analysis of variance indicate which of the following?
There is no interaction between factors A and B.
What is stated by the null hypothesis for the chi-square test for independence?
There is no relationship between the two populations regarding the two variables.
When comparing more than two condition means, why should an analysis of variance be used instead of multiple t tests?
Using multiple t tests increases the risk of type I error.
Under which circumstances is the phi-coefficient used?
When both variables are dichotomous
Under which conditions is Cramérs V used to measure the effect size for a chi-square test for independence?
When either of the two variables consists of more than two categories
What is assumed by the homogeneity a variance assumption?
Whether to populations have equal variances
In a two factor analysis of variance, a main effect is defined as _______.
You mean differences among the levels of one factor.
On average, which values expected for the F-ratio if the null hypothesis is false?
an F value much greater than 1
And a repeated-measures experiment, each individual participates in one treatment condition and then moved on to a second treatment condition. One major concern in this type of research study is at the participation in the first treatment may influence in individual score in the second treatment. What is his problem called?
an order effect
The Pearson correlation is calculated for a sample of n = 20 individuals. If a hypothesis test is used to determine whether the correlation is significant, which df value would be used for the t statistic?
df = 18
A researcher uses a repeated-measures study to compare two treatment conditions with a set of 20 scores in each treatment. What is the df value for the repeated-measures t statistic?
df = 19
An independent-measures research study uses n = 15 participants in one group and n= 12 participants in the second group to compare to treatment conditions. What is the df value for the t-statistic computed for the corresponding hypothesis test?
df = 25
An ANOVA is used to evaluate the main differences among three treatment conditions with a sample of n = 12 participants in each condition. For this research study, what is dfbetween?
dfbetween = 2
An ANOVA is used to evaluate the main differences among three treatment conditions with a sample of n = 12 participants in each condition. For this research study, what is dftotal?
dftotal = 35
And ANOVA is used to evaluate the main differences among three treatment conditions with a sample of n = 12 participants in each condition. For this research study, what is dfwithin?
dfwithin = 33
A research report describing the details from a repeated-measures t test states that "t(23) = 1.71, p > .05." Which Option below is consistent with this statement?
n = 23 and failing to reject the null hypothesis
Which correlation should be used to measure the relationship between gender and grade point average for a group of college students?
point-biserial correlation
A researcher assesses self-esteem among college students at the beginning of the semester using a self-report questionnaire, as well as three months later at the end of the semester among the same sample of college students using the exact same self-report measure of self-esteem. The researcher determines that there is a significant positive relationship between self-esteem measured the beginning and at the end of the college semester for the student sampled. This demonstrates how correlations can be used to demonstrate _____.
reliability
A researcher and covers that there is a significant interaction between the factor of marital status (i.e., married or not married) and participant sex (i.e., male or female) with regard to health well-being. A researcher decides to compare the difference in health well-being between married men and women this is an example of testing a(n) _____
simple main effect
For a two-tailed hypothesis test evaluating a Pearson correlation, what is stated by the null hypothesis?
the population correlation is zero.
In general, what characteristics of difference scores are most likely to produce a statistically significant t statistic for a repeated measures-hypothesis test?
A large sample size and a small variance
The results from a two-factor analysis of variance show a significant main effect for factor A and a significant man effect for factor B. Based on this information, what can a researcher conclude about the interaction?
A researcher cannot make any conclusion about the statistical significance of the main effects.
In general, what is the effect of an increase in the variance for the sample of difference scores?
An increase in the estimated standard error and a decrease in the value of t
