Review Final Psych 202
Systematic variance
between-group variance)
A researcher replicates a past study that manipulates the physical attractiveness of a defendant by using photographs instead of written descriptions. This technique would be an example of _____ replication.
conceptual
The significance level chosen by a researcher is dependent on the _____.
consequences of making a Type I versus a Type II error
Single-case experiments were developed from a need to:
determine whether a manipulation has an effect on a single research participant.
The expected value of t under the null hypothesis _____.
equals 0
Type 1 error
false positive- conclude that something is different when it is not
Statistically, significant results mean that the results are:
likely to be due to true differences between the groups.
A. Central Tendency
mean, median, mode
Mode
most frequent score
Mean (M)
obtained by adding all the scores and dividing by the number of scores
A regression equation is used to:
predict a score for Y from a known score of X.
Adrian found no significant difference in the amount of money spent on entertainment on those students who live on campus versus those who live off campus. Based on this finding, Adrian would:
reject the null hypotheses
Sumaira took an aptitude test for a position with Accountants Unlimited. She was hired the following week. In this scenario, the predictor variable is Sumaira's _____.
score on the aptitude test
Median (Mdn)
score right in the middle, bitch. you know this.
With respect to Pearson r, the absolute size of r is the coefficient that indicates the:
strength of the relationship between two variables
In a multiple baseline across situations design, _____.
the same behavior is measured in different settings
The null hypothesis is rejected whenever:
there is a low probability that the obtained results could be due to random error.
When comparing the differences in the ratings of responsibility for an automobile accident between male and female drivers, the null hypothesis would suggest that:
there is no difference in the ratings of responsibility between male and female drivers.
A correlation coefficient is always used _____.
to describe the strength of the relationship between two variables
One solution to the problem of generalizing to other experimenters is to use _____.
two or more experimenters
probability is very low
we reject the possibility that only random or chance error is responsible for the obtained difference in means
Error variance
within-in group variance
HISTOGRAMS
-Graph title and labeled axes -bars do touch -vertical scale is frequency -numerical data
Null hypothesis
-H0 - Population means are equal -Observed difference due to random error -Independent variable had no effect
Research hypothesis
-H1 - Population means are not equal -Independent variable had an effect
Sampling distributions
-Probability distribution of a given statistic based on a random sample -Based on the assumption that the null hypothesis is true
BAR GRAPHS
-graph title and labeled axes -Bars do not touch -Vertical scale is frequency -Categorical data
Regression toward the mean
A graduating college student takes the Graduate Record Exam and scores high marks. Six months later the student retakes the exam after completing all undergraduate coursework, but scores relatively low. Other than the boring coursework, what is most likely to account for the lower scores?
Identify the risk associated with pretests.
A pretest tends to induce subjects to behave differently than they would without the pretest.
B. Ordinal
A professor at a university ranks subjects based on students' preferences identified through a survey. He ranks science first, mathematics second, and management third. What type of measurement scale has the professor employed?
C. one-tailed t-test
A researcher wants to test a hypothesis according to which the mean rating of guilt will be higher for unattractive defendants than for attractive defendants. The appropriate statistical test would be the _____.
D. F-test
A student is interested in the effect of environmental conditions on task performance. She makes participants complete a series of math problems under different conditions of temperature—cold, warm, and hot, and different noise conditions—quiet and noisy. The most appropriate test to analyze the data would be a(n) _____.
C. Median
A teacher displays the results of a test on a notice board. As per the results, half the students scored more than 70 percent in the test, while the remaining scored less than 70 percent. Which measure of central tendency does this scenario represent?
Across behaviors multiple-baseline design
Amelia realized that her 7-year-old daughter, Violet, was especially motivated by money. Amelia began a reinforcement program whereby Violet earned 5 cents every time she brushed her teeth. A month later, Amelia instituted a payment schedule of 10 cents every time Violet went to bed on time without complaining. Once these behaviors were firmly established, Violet began earning money for every book she read. What kind of single-subject design did Amelia employ?
Which of the following examples best represents the use of an interval scale?
B. Assessing students' ratings of their professors' performance on a five-point scale ranging from poor to excellent
Which of the following statements is true about ratio scales?
B. They have an absolute zero point.
The probability of making a Type II error increases when the
B. effect size is small.
Dr. Paul found that college students between the ages of 18 and 23 performed better on a cognitive task in a low-noise condition than in a high-noise condition. Dr. Ben wants to repeat Dr. Paul's study by adding age as a variable—18-23 and 65-74. He predicts an interaction between the age and noise variables. In this case, Dr. Ben is questioning the _____ validity of the original study.
B. external
A Type I error occurs when one:
B. rejects the null hypothesis when it is true.
In attempting to study police officers' attitudes toward their supervisors, Alex surveys 25 police officers working in the day shift. In this case, what can help Alex ensure that his findings have external validity?
C. Surveying officers from all shifts in the department
What is most likely to be true of a study conducted on a group of males to analyze the effects of room temperature on task performance?
C. The findings of the study cannot be generalized to females.
Which of the following statements is true about bar graphs?
C. They use a separate and distinct bar for each piece of information.
A(n) _____ replication is an attempt to replicate precisely the procedures of a study to see whether the same results are obtained.
C. exact
When the results of a study can be generalized to other subject populations, the study is said to have _____ validity.
C. external
REGRESSION
Can be used to make prediction about 1 variable from another known variable Must have high correlation Must be linear! - uses calculations used to predict a person's score on one variable
DESCRIBING RESULTS
Comparing group percentage Correlating individual scores Comparing group means
Which significance level would minimize the probability of a Type I error?
D. .01
Why are conceptual replications considered important in the field of social sciences?
D. They use complex variables that can be operationalized in different ways.
A Type II error occurs when one:
D. accepts the null hypothesis when it is false
When testing the differences between means, the null hypothesis suggests that any observed difference is due to _____.
D. random error
Correlation coefficient
Describes how strongly variables are related to one another
Power of statistical test:
Determines optimal sample size based on probability of correctly rejecting the null hypothesis
One group pretest-posttest design
Dr. Jayden is studying the effect of exercise on cholesterol level. He first measures his patients' cholesterol level before recommending an exercise program and after one month of participating in an exercise program, he measures their cholesterol level again. What type of research design has Dr. Jayden employed?
C. literature review
Elaine has read a number of studies on the effect of physical attractiveness on the judgment of an individual's personality characteristics. She then writes a paper in which she categorizes the findings and draws conclusions based on her summaries of the studies. Elaine has most likely conducted a _____.
Ratio
Equal intervals Absolute zero (ex. time, weight, length, & other physical measures) Can be summarized using mean or arithmetic average
D. Type II
Ethan concludes that there is no difference in the driving ability of drivers who have consumed one can of beer and those who have consumed three cans of beer. However, there actually is a difference in the driving ability of the drivers. In this case, Ethan has made a(n) _____ error.
history
Events that occur between the first and second measurement period but are not part of the manipulation are called _____ effects.
t test:
Examines whether two groups are significantly different from each other t value - Ratio of two aspects of data
External validity:
Extent to which findings may be generalized
Type 2 error
False negative- say nothing is going on when something is
Three claims
Frequency Association Causal
What refers to external validity?
Generalizability of the research findings
Inferential statistics
Give the probability that the difference between means reflects random error rather than a real difference - are used to make conclusions about the data
Central Tendency
How participants scored overall
Variability
How widely the distribution of scores is spread
meta-analysis
In a _____, the researcher combines the actual results of a number of studies in which the analysis consists of a set of statistical procedures that employ effect sizes to compare a given finding across many different studies.
Cohort
In a cross-sectional study, a difference among groups of different ages may reflect developmental age changes; however, these differences may result from _____ effects.
chance fluctuations.
In an ABAB reversal design, the second "B" period is necessary to rule out:
there is no control group.
In order to study the effects of watching violent programs on children's aggressiveness, a researcher observes children's behavior after they watch 30 minutes of violent programs on television. The researcher concludes that television violence causes aggressiveness. A problem in this research is that:
participants change over time and become bored or fatigued.
In the context of one-group pretest-posttest design, maturation effects occur when:
Statistical significance
Indicates that there is a low probability that the difference between the obtained sample means was due to random error
Aden finds that, on an average, men have higher starting salaries than women. In order to conclude that the differences in starting salaries are true differences and not a result of random error, Aden would employ the use of _____ statistics.
Inferential
Interval
Intervals between levels are equal in size Can be summarized using mean or arithmetic average No absolute zero
Probability
Likelihood of the occurrence of some event or outcome
Nominal
No numerical, quantitative properties Levels represent different categories or groups
Degrees of freedom (df):
Number of scores free to vary once the means are known
Across subjects multiple-baseline design
Professor Aaron finds that when he smiles and makes eye contact with Jeanne, she becomes more responsive to his questions. He tries the same behavior on David, Chris, and B.J. and finds that it also influences their responses to his questions. What type of single-case design did Professor Aaron employ?
Ordinal
Rank the levels from lowest to highest
A. Nominal
Researchers studying the effectiveness of a diet on heart disease divided the study's participants into two groups—those with Type A personalities and those with Type B personalities. Which scale of measurement characterizes these personality variables?
Which of the following describes a sequential design?
Studying groups of 10- and 15-year-olds, and then studying these individuals 2, 4, and 6 years later
What does a Solomon four-group design assess?
The impact of taking the pretest
group percentages.
The principal of a school conducts a survey to compare the number of third grade and sixth grade students who buy their lunch at school. The most appropriate way to describe the results of this survey would be to compare:
Dana measures the height of four- and five-year-olds. To her surprise, she finds no correlation between height and age. What is most likely responsible for this result?
The range of the variables has been restricted.
selection differences
The serious flaw associated with the nonequivalent control group design is that
F test or analysis of variance:
There are more than two levels of an independent variable Factorial design with two or more independent variables has been used
A researcher asked participants to rate the quality of two well-known brands of paper bags—Prime and Zenith. Prime was rated higher than Zenith with mean ratings of 5.50 and 3.25 respectively. This difference was statistically significant at the .05 probability level. The research hypothesis for this study suggests that:
There is a difference between Prime and Zenith in terms of quality.
ABA
To examine how a reward influences a desired behavior, a mother first counts the number of times her son makes his bed over a two-week period. For the next two weeks, she gives him a reward every time he makes his bed. Following this period, she stops rewarding him and again counts the number of times he makes his bed. This procedure would be an example of a(n) _____ design.
Sample size
Total number of observations
Pearson product-moment correlation coefficient (Pearson r)
Used when both variables have interval or ratio scale properties Provides information about the strength and the direction of relationship Values range from 0.00 to ±1.00 Can be described visually using scatterplots
B. have a value of 0.00.
When the independent variable has no effect on the dependent variable, the effect size statistic will:
C. Between-groups variance = systematic variance
Which of the following accurately describes the relationship between concepts?
Cross-sectional and longitudinal research designs
Which of the following are two general methods for studying individuals of different ages?
The same children are tested at 1, 3, 5, and 10 years of age.
Which of the following best describes a longitudinal study on children's development?
C. Range
Which of the following is a measure of variability?
Causal inference
_____ in quasi-experimental designs is more difficult than in true experiments because quasi-experimental designs lack the important features of true experiments such as random assignment to conditions.
A. Error
_____ variance is the deviation of the individual scores in each group from their respective group means.
Which of the following would a researcher be least likely to do when conducting a literature review?
a researcher is least likely to calculate an effect size for all the studies reviewed.
DESCRIPTIVE STATISTICS
allow researchers to make precise statements about the data -needs central tendency -variability
