PSYC 4703- Statistics and Research Methods II

On average, which value is expected for the F-ratio if the null hypothesis is true?

F = 1

Under what circumstances can a very small treatment effect be statistically significant?

If the sample size is large and the sample variance is small.

Which of the following bits of information is referenced last in an APA formatted statistical report of the results regarding a two-factor ANOVA?

Partial eta squared as a measure of effect size

The null hypothesis for a repeated-measures test states which of the following?

The entire population will have a mean difference of μD=0.

What is referred to by the term observed frequencies?

The frequencies found in the sample data classified into each category.

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.

Which of the following statements is not consistent with the assumptions necessary when computing a repeated-measures t statistic?

The scores between each treatment must be independent.

In an ANOVA, what is represented by the letter T?

The sum of the scores in a specific condition.

In an ANOVA, what is represented by the letter N?

The total number of scores in the entire research study.

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.

What is assumed by the homogeneity of variance assumption?

Whether two populations have equal variances

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

Which of the following Pearson correlations show the greatest strength or consistency of relationship?

r = -0.90

Which of the following is consistent with the alternative hypothesis regarding the main effect of Factor B, which is comprised of two levels?

μB1 ≠ μB2

A chi-square test for goodness of fit has a df = 2. How many categories were used to classify the individuals in the sample?

3

The results from a two-factor ANOVA show a significant main effect for factor A and a significant main 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 interaction.

For an 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 ANOVA, differences between participants contribute to which of the following variances?

Both between-treatments variance and within-treatments variance

Suppose the correlation between height and weight for adults is r = +0.40. Which proportion (or percent) of the variability in weight can be explained by its relationship with height?

16%

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 a statistically significant difference than a Tukey post hoc test.

A researcher measures IQ and weight for a group of college students. Which kind of correlation is likely to be obtained for these two variables?

A correlation near 0.

Which of the following is an accurate distinction between repeated-measures and independent-measures research designs?

In repeated-measures research designs, each participant is measured once on the same variable.

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.

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 ANOVA test be used instead of multiple t tests?

Using multiple t tests increases the risk of a Type I error.

Under which circumstances is the phi-coefficient used?

When both variables are dichotomous.

Under which conditions is Cramer's 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.

Which of the following elements is always presented last in a statistical report statement describing the results of an independent-measures t test?

effect size

For the repeated-measures t statistic, df =

n — 1

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 at the beginning and end of the college semester for the students sampled. This demonstrates how correlation can be used to demonstrate

reliability.

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

If a treatment is expected to increase scores on a variable for which the mean is expected to be μ = 100, what is the null hypothesis?

μ with treatment ≤ 100

Which of the following is the correct null hypothesis for an independent-measures t test?

μ1 — μ2 = 0

Which of the following is the correct alternative hypothesis for an independent-measures t test?

μ1 — μ2 ≠ 0

For the independent-measures t statistic, what is the effect of increasing the sample variances?

A decrease in the likelihood of rejecting the H0 and a decrease in measures of effect size.

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.

Which of these examples violates a basic assumption for a chi-square hypothesis test?

A participant produces responses that can be counted twice in the same category.

A researcher plans to conduct a research study comparing two treatments conditions with a total of 20 participants. Which of the following designs would produce 20 scores in each treatment?

A repeated-measures design

If a two-factor ANOVA produces a statistically significant interaction, what can you conclude about the main effects?

A researcher cannot make any conclusion about the statistical significance of the main effects.

All else constant, which combination of factors would increase the width of a confidence interval most?

A smaller sample size and a larger confidence interval.

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.

For the independent-measures t statistic, what is the effect of increasing the difference between 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.

In a repeated-measures experiment, each individual participates in one treatment condition and then moves on to a second treatment condition. One major concern in this type of research study is that participation in the first treatment may influence an individual's score in the second treatment. What is this problem called?

An order effect

How are the degrees of freedom calculated for the chi-square goodness of fit test?

C - 1

For which of the following situations would a repeated-measures research design be appropriate?

Comparing pain tolerance with and without acupuncture needles.

Which bit of information is not obtainable from the results of the t-test written up in a statistical report?

Each of these bits of information is obtainable from the results of a t-test written up in a statistical report.

Which of the following is an accurate comparison between the expected and observed frequencies for a chi-square test?

Expected frequencies can contain fractions or decimal values, and observed frequencies are always whole numbers.

What is indicated by a positive value for a correlation?

Increases in X tend to be accompanied by increases in Y.

If the mean and variance are computed for each sample in 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 sample variance influence the estimated standard error and measures of effect size such as r2 (r squared) and Cohen's d?

Larger sample variance increases the estimated standard error but decreases measures of effect size.

In a two-factor experiment with 2 levels of factor A and 2 levels of factor B, three of the treatment means are essentially identical and one is substantially different from the 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 deviations for all factor conditions

Which of the following describes the effect of an increase in the variance of the difference scores in a repeated-measures design?

Measures of effect size and the likelihood of rejecting the null hypothesis both decrease.

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.

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.

What would the scatter plot show for data that produce a Pearson correlation of r = +0.88?

Points clustered close to a line that slopes up to the right.

For a group of graduating college seniors, a researcher records each student's rank in his/her high school graduating class and the student's rank in the college graduating class. Which correlation should be used to measure the relationship between these two variables?

Spearman correlation

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 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.

Which of the following best describes the possible value for a chi-square statistic?

The chi-square statistic is always positive but can contain fractions or decimal values.

Assuming all other factors are held constant, if the df value for a two-tailed t-test with α=.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.

What is referred to by the term expected frequencies?

The frequencies computed from the null hypothesis.

In a two-factor ANOVA, a main effect is defined as

The mean differences among the levels of one factor

Which of the following is consistent with the alternative hypothesis for the interaction of factors A and B in a two-factor ANOVA?

The mean 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.

For a two-tailed hypothesis test evaluating a Pearson correlation, what is stated by the null hypothesis?

The population correlation is zero.

Which of the following is consistent with what r2 (r squared) represents as a measure of effect size?

The portion of variability in a sample attributable to a treatment effect relative to the total variability in the sample.

A repeated-measures research design tends to have which of the following drawbacks?

The possibility for extraneous variables that occur over the passage of time to influence results.

A researcher obtains a negative value for the chi-square statistic in a chi-square goodness of fit test. hat can a researcher conclude based on this result?

The researcher made a mistake because the chi-square value cannot be negative.

Which of the following describes the effect of increasing sample size in a 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.

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 statements for other types of statistical test (e.g., t-test, ANOVA)?

sample size (n)

A researcher assesses work ethic among college students using a self-report questionnaire. Moreover, the researcher tracks how many hours students seek out extra support at the tutoring center 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.

On average, which value is expected for the F-ratio if the null hypothesis is false?

An F value much greater than 1.

Which of the following statements accurately describes the chi-square test for independence?

It is similar to both a correlational and an independent measures t test because it can be used to evaluate a relationship between variables or a difference between populations.

Which correlation should be used to measure the relationship between gender and grade point average for a group of college students?

Point-biserial correlation

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.

For an ANOVA comparing three treatment conditions, what is stated by the null hypothesis (H0)?

There are no differences between any of the population means.

Two crossing, non-parallel lines in a graph pertaining to separate factors (i.e., A & B) in a two-factor ANOVA indicate which of the following?

There is an interaction between factors A and B.

Two parallel lines in a graph pertaining to separate factors (i.e., A & B) in a two-factor ANOVA indicate which of the following?

There is no interaction between factors A and B.

The data for a chi-square test consists of

frequencies

A researcher uncovers 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 and well-being between married men and women. This is an example of testing a(n)

simple main effect

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 tests in scientific reports?

t(19) = 2.30, p < .05, r2 = 0.42

Which of the following is consistent with the null hypothesis regarding the main effect of Factor A, which is comprised of two levels?

μA1 = μA2