All GRE Subject Test: Psychology Resources
Example Questions
Example Question #11 : Statistical Procedures
Which of the following best describes the mean of a Z-score?
The mean of a Z-score is zero. This means that the score is the same as the mean. A positive or negative Z-score would show that it is above or below the mean and by how many standard deviations.
Example Question #12 : Statistical Procedures
A distribution that has a tail that is longer on the right side is considered to be which of the following?
None of these
Positive distribution
Negative distribution
Normal distribution.
Positive distribution
The distribution is positive because its tail goes to toward the right. If it were negative, the tail would go toward the Y-axis, or the left. If a distribution's tail is longer on either side, then it is not a normal distribution. It is not symmetrical and would be classified as a skewed distribution.
Example Question #13 : Statistical Procedures
A correlational study most likely possesses which of the following?
A relationship but not causality
Neither a relationship nor causality
A cause and effect
A relationship and causality
A relationship but not causality
A correlational study looks at the relationship between two or more variables. For example, the relationship between test scores in math and history classes. It does not try to find a cause and effect between the variables, and the researcher does not manipulate the variables. The researcher is simply trying to see if they possess a relationship or correlation.
Example Question #14 : Statistical Procedures
What does the following symbol indicate?
"The sum of"
"The quotient of"
"The difference of"
"The product of"
"The sum of"
This symbol represents a command to find the sum of two or more numbers. This symbol is the Greek letter 'E' and is used in a variety of equations. It is called Epsilon.
Example Question #31 : Measurement & Methodology
Which of the following terms is defined as the descriptive statistic that measures the degree of the relationship between two variables?
Dependent variable
Correlation coefficient
Independent variable
Mode
Correlation coefficient
The correct choice is “correlation coefficient.” Independent and dependent variables do not measure anything but are simply components of the study itself. The mode is the value that occurs the most in a set of numbers.
Example Question #32 : Measurement & Methodology
Which of the following indicates the average amount of variability observed in particular types of scores (e.g. test scores)?
Range
Standard deviation
Mean
Median
Mode
Standard deviation
The “standard deviation” is a measure of variability, or spread of scores. This measure is calculated by subtracting each score from the mean, squaring the result, dividing this result by the total number of scores, and finally taking the square root of the last calculation. The “range” is also a measure of variability but its calculation involves subtracting the highest and lowest scores; therefore, it is not an average. The mean, median, and mode are measures of central tendency. The “mean” is the average of all scores. The “median” is the middle score, or average of the two middle scores. Last, the “mode” is the score that occurs most frequently.
Example Question #33 : Measurement & Methodology
In a negatively skewed distribution, which of the following is true?
The median is the highest score
The mean and median are equal, and are higher than the mode
The mean is the highest score
The mode is the highest score
The mode and median are equal, and are higher than the mean
The mode is the highest score
In a negatively skewed distribution, the tail of the distribution falls on the left or negative side of the distribution. The mode is always the highest score, followed by the median, and lastly the mean. The opposite is true for a positively skewed distribution. In a normal distribution, the mean, median, and mode are all equal.
Example Question #43 : Other Areas
Karen received a raw score of on an exam with a mean score of and a standard deviation of . What is Karen's Z-score?
The exam had a mean of and a standard deviation of . Karen received a raw score of , which is points above the mean. In order to calculate her Z-score you must use the Z-score formula:
Karen's Z score is +2.
You would also be able to guess the correct answer by drawing a picture of a normal curve. You can then see that Karen's score is above the mean, which tells you that her Z-score must be positive.
Example Question #11 : Statistical Procedures
Carla, Bob, and Jimmy all took the same exam. Carla received a T-score of 65, Bob received a Z-score of 1.25, and Jimmy received a standard score of of 85. Who received the highest Z-score on the exam?
Bob
Jimmy
Bob and Jimmy have equal Z scores, and scored higher than Carla
Cannot be determined
Carla
Carla
In order to determine the answer to this question you must have knowledge of T-scores, standard scores, and Z-scores. T-scores always have a mean of 50 and a standard deviation of 10. Carla had a T-score of 65, which is 1.5 standard deviations above the mean, and is equivalent to a Z-score of 1.5. Bob received a Z score of 1.25, which is lower than Carla's Z-score. Standard scores always have a mean of 100 and a standard deviation of 15. Jimmy received a standard score of 85, which is one standard deviation below the mean and equal to a Z-score of -1. Carla had the highest Z-score.
Example Question #34 : Measurement & Methodology
Dr. G is conducting a research study looking at whether or not a new drug decreases depression. She falsely concludes that the drug is ineffective at decreasing depression. Dr. G has committed which of the following?
Power
Clinical significance
Type III error
Type II error
Type I error
Type II error
"Type II error" involves failing to reject a null hypothesis when it is false. This occurs when a researcher says that the findings are not significant, when in fact they are. "Type I error" is the opposite, and involves rejecting the null hypothesis when it is true. "Power" is the likelihood of rejecting the null when it is false, and is desirable in a research study. Last, "clinical significance" is similar to power and is what researchers aim for. It is important to note that "type III error" is not a term used in statistics.