GRE Subject Test: Psychology : Other Areas

Study concepts, example questions & explanations for GRE Subject Test: Psychology

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Example Questions

Example Question #51 : Other Areas

Which statistical procedure is best used when there are two or more independent variables, the variables can be held fixed with respect to each other, and a conditional expectation of dependent variable given the independent variables is required?

Possible Answers:

All of these

Regression analysis

Analysis of covariance (ANCOVA)

Two-way ANOVA

Spearman's rank-correlation coefficient

Correct answer:

Regression analysis

Explanation:

A regression analysis, so long as all but one independent variable at a time can be held fixed, is able to produce a predictive window called a conditional expectation that allows for prediction of dependent variable values given set independent variable levels.

Example Question #52 : Other Areas

The primary difference between a sequential sum of squares and an adjusted sum of squares is that the adjusted sum of squares __________.

Possible Answers:

only works for models with small values for n

only works for models with large values for n

depends on the order in which factors are entered into the model

does not depend on the order in which factors are entered into the model

None of these

Correct answer:

does not depend on the order in which factors are entered into the model

Explanation:

An adjusted sum of squares is a model that determines the amount of remaining variance in a model is explained by a factor given that all the other factors are already in the model. For a sequential sum of squares, the amount of variance in a model is explained only given the factors which are already in the model. Thus, the first factor inserted in a sequential sum of squares carries the most weight.

Example Question #53 : Other Areas

All of the following are true about the General Linear Model (GLM) except which of the following?

Possible Answers:

It incorporates F-testing, t-testing, linear regression, and ANOVA models

It can test hypotheses using either multivariate or multiple independent univariate tests

It works irrespective of the error terms in each matrix

It generalizes multiple linear regression to more than one dependent variable

All of these

Correct answer:

It works irrespective of the error terms in each matrix

Explanation:

The general linear model, expressed as , works by comparing a model matrix (sometimes called a design matrix) to a parametric estimate, while also factoring for generalized error terms within the data. It works best when errors are uncorrelated across measurements.

Example Question #54 : Other Areas

One appropriate use of a biased ANOVA term for expected mean squares might be which of the following?

Possible Answers:

None of these

If one or more terms are nonparametric in the model

If the population means are not equal to one another (the null hypothesis is false)

If the population mean cannot be estimated

If the factors are expected to have an interaction

Correct answer:

If the population means are not equal to one another (the null hypothesis is false)

Explanation:

A biased EMS is most commonly used when random terms are part of the factors in the model (and thus, when the population means cannot be reasonably assumed to be equal irrespective of treatment effect).

Example Question #55 : Other Areas

All of the following are true about Pearson's r except which of the following?

Possible Answers:

Confidence intervals cannot be established for weak values of r

Sample r is extremely accurate at estimating population correlation coefficients if sample size is large

Sampling distribution can be made to fit Student's t-distribution

All of these

Strength of correlation ranges from -1 to 1

Correct answer:

Confidence intervals cannot be established for weak values of r

Explanation:

Constructing a confidence interval for Pearson's r can be done through a process called "bootstrapping", which involves re-sampling with replacement a certain number of values in each correlation a large number of times.

Example Question #211 : Gre Subject Test: Psychology

Which of the following is a situation where you might prefer a one-tailed test to a two-tailed test?

Possible Answers:

When only deviations above a particular score are of research interest

None of these

When comparisons between groups are more important then comparisons across groups

When the sample size is excessively low

When the sample size is excessively high

Correct answer:

When only deviations above a particular score are of research interest

Explanation:

A two-tailed test differs from a one-tailed test primarily in that it examines deviations both above and below a particular mean. Thus, a one-tailed test is most appropriate when only one direction of deviation is of relevant interest.

Example Question #212 : Gre Subject Test: Psychology

Each of the following is true about homoscedasticity except which of the following?

Possible Answers:

None of these

It follows the assumption that standard deviations of the error terms are constant within measures

It can be tested by regression of squared residuals

It largely determines goodness of fit (as defined by Pearson's r)

Meeting the assumption of homoscedasticity is necessary to demonstrate an unbiased estimate

Correct answer:

Meeting the assumption of homoscedasticity is necessary to demonstrate an unbiased estimate

Explanation:

Homoscedasticity is explicitly not required to ensure unbiased, asymptotically normal, or reliable results. They are, however, required to show goodness of fit.

Example Question #213 : Gre Subject Test: Psychology

When testing for non-groupwise homogeneity of variance, the most sensitive test to departures from normality is generally which of the following?

Possible Answers:

Bartlett's test

Brown-Forsythe test

None of these

Goldfeld-Quandt test

Levene's test

Correct answer:

Bartlett's test

Explanation:

Levene's test and the Brown-Forsythe test for homogeneity of variance are not very sensitive to departures from normality, which makes them more useful as tests for nonstandard data sets but less able to predict goodness of fit. Goldfeld-Quandt is a test for groupwise homogeneity of variance, and is useless for the stated purpose.

Example Question #214 : Gre Subject Test: Psychology

Dr. Crawford believes she has invented a pill to help with student memorization. For a trial experiment, she gathered two groups of twenty students. She gave the twenty students in Group A the “smart pill”, and the twenty students in Group B a sugar pill. After waiting five minutes, both groups of students were given a list of forty words, and were instructed to memorize the entire list in any order. The students were given five minutes to memorize the list. The students were then asked to verbally recite all of the words they could remember in any order within three minutes.

Group A recited an average of fifteen words, while Group B recited an average of ten words.

Which statistical analysis should Dr. Crawford use?

Possible Answers:

Cannonical correlation

ANOVA

T-test

Pearson-R

Chi-square

Correct answer:

T-test

Explanation:

A t-test is most appropriate when only analyzing two variables. Dr. Crawford is analyzing the means between Group A, who received the smart pill, and Group B, who did not. This test will determine whether the differences in means is due to chance or if there is a statistically sound significant difference.

Example Question #31 : Statistical Procedures

Dr. Crawford believes she has invented a pill to help with student memorization. For a trial experiment, she gathered two groups of twenty students. She gave the twenty students in Group A the “smart pill”, and the twenty students in Group B a sugar pill. After waiting five minutes, both groups of students were given a list of forty words, and were instructed to memorize the entire list in any order. The students were given five minutes to memorize the list. The students were then asked to verbally recite all of the words they could remember in any order within three minutes.

Group A recited an average of fifteen words, while Group B recited an average of ten words.

Dr. Crawford can for sure reject her null hypothesis if she obtains a calculated p-value equal to which of the following?

Possible Answers:

None of these

Correct answer:

Explanation:

The p-value represents the probability that differences in means are due to random chance and not due to the independent variable’s effects. The smaller the p-value, the less likely it is that differences in means are random. This supports the researcher rejecting the null hypothesis; therefore, the following p-value is the correct answer:

All GRE Subject Test: Psychology Resources

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