Chapter #2
Professor Yoon is testing the effects of alcohol consumption on driving ability. He will divide his 100 participants (all over age 21) into four groups. Which of the following would be the best way to assign participants to the experimental and control groups?
random assignment
Which of the following correlation coefficients would you expect to see between month of birth (1 through 12) and scores on an intelligence test?
r = -0.02
Which of the following is a correct representation of a strong negative correlation?
r = -0.82
Professor Zhang found a correlation of -0.76. What data could this correlation represent?
the relationship between antidepressant dose and depressive symptoms
What is the first step of the scientific method?
to ask a question
Scatterplots show:
two scores represented as individual points on the graph
If high values in one variable are associated with both high and low values of the other variables, the variables are:
uncorrelated
Dr. Velasquez found a correlation of r = 0.02 in a recent study. The two variables in his study are:
uncorrelated.
Sophia is conducting a long-term study of intelligence, asking if it changes significantly as people age. In this study, intelligence would be considered a:
variable
Jared has been trying to come up with a research question for his senior thesis. He asks his psychology instructor for recommendations. She suggests all of the following except:
"Establish operational definitions to specify variables being studied."
The relationship between time spent studying and the number of pillows in your house is probably best described by which of the following correlation coefficients?
-0.02
Which of the following correlation coefficients represents the weakest negative correlation?
-0.20
The more Brandon cleans his kitchen, the less dirt he sees on the counters and floor. In this example, the correlation between the variables "amount of cleaning" and "amount of dirt" would be best described by which of the following correlation coefficients?
-0.79
Correlation coefficients can range from:
-1 to 1
Which of the following correlation coefficients may represent a strong positive correlation?
0.80
What is the mode in the following data set: 2 2 2 3 5 6 6 7?
2
What is the mean in the following data set: 2 3 4?
3
What percentage of IQ scores, such as those obtained with the WAIS or WISC, fall within 3 standard deviations of the mean?
99.7%
Why can't one state that a correlation between two variables indicates that a change in one causes a change in the other?
Because a third variable may have influenced the results.
Why is the scientific method considered to be a "cyclical" process?
Because the findings of one study often lead to questions that are the basis for future research.
What is the second step of the scientific method?
Form a hypothesis
Scientific Method
Observation, Question, Theory, Hypothesis, Experiment, Data, Conclusion
The correlation coefficient is represented by:
R
_____ is used at the onset of a study to gather participants from a larger population, while _____ comes into play later, when you are putting participants in different groups.
Random selection; random assignment
__________ is the only type of research method that can determine cause-and-effect relationships between variables.
The experimental method
In a depiction of a perfect negative correlation (-1.00), which of the following shapes would you most likely see on a scatterplot?
a diagonal line that moves from the top left to the bottom right
Dr. Marvin is conducting a study to determine whether a new medication is effective in reducing pain associated with migraines. His study is funded by a grant from the pharmaceutical company that developed and produces the medication. Given the potential for experimenter bias in this study, what method should be employed to make sure Dr. Marvin's expectations and unintentional behaviors do not unwittingly change the outcome of the study?
a double-blind study
SCATTERPLOT
a graphed cluster of dots, each of which represents the values of two variables
Professor Andrews found that as the number of days absent increases, students' grades decrease. Professor Andrews has found:
a negative correlation between days absent and grades.
Professor Hartwick finds that people who tend to score low on one variable tend to score low on another variable. Professor Hartwick has found:
a positive correlation
Michael notices that the plants in his garden that are in the shade most of the day are smaller than the ones that are in the sun. What can Michael conclude about the relationship between sunlight and plant growth?
a positive correlation between amount of sunlight and plant growth
Professor McManus shows a scatterplot of data that show that grades increase as the number of hours spent studying increases. Professor McManus has shown:
a positive correlation between studying and grades.
CORRELATION COEFFICIENT
a statistical measure of how much two factors vary together (and thus, how well either predicts the other); referred to as r
CORRELATION
a statistical measure that indicates the extent to which two factors vary together and thus, how well either factor predicts the other
CORRELATION ANALYSIS
a statistical technique that indicates the extent to which two factors vary together and thus, how well either factor predicts the other
Dr. Segal predicted that identical twins would cooperate more and compete less than fraternal twins when performing a joint task. She and her colleagues videotaped sets of identical and fraternal twins working together on puzzles, and then rated the children's behavior using measures of cooperative behavior. How should she determine if her hypothesis was correct?
by analyzing the data
After Carolyn is done analyzing her research, she leaves the participants' names and phone numbers on her desk when she leaves for the day. Although her office is locked, she forgets that the custodian comes in after hours to empty the trash can and sweep the floor. Carolyn has unintentionally neglected the ethical consideration of:
confidentiality
Which is an ethical guideline in psychology?
confidentiality
NO CORRELATION
correlation coefficient is near zero
NOT CORRELATED
correlation coefficient is near zero
UNCORRELATED
correlation coefficient is near zero
Which of the following is not part of the process of developing a hypothesis?
deciding whether the study will employ descriptive or experimental methods
_____ statistics are used to organize and present data, often through tables, graphs, and charts.
descriptive
The scientific method consists of several steps that progress in a sequence. The first step in that sequence is to:
develop a question
A graph of the relationship between two positively correlated variables would show a(n):
diagonal line from the lower left to the upper right.
A graph of the relationship between two negatively correlated variables would show a(n):
diagonal line from the upper left to the lower right.
Dr. Gonzalez is conducting an experiment on water consumption and exam performance. She divides participants into three groups: no extra water, two 8-ounce cups of water, and four 8-ounce cups of water. She then compares the average exam scores for the groups to see if water consumption before exams influences participant performance. In this study, the dependent variable is:
exam scores
Lillard & Peterson (2011), randomly assigned children to one of three 9-minute activity conditions: Watching <i>SpongeBob SquarePants,</i> watching an educational program, or drawing and coloring. All the children's performance on cognitive tasks was then assessed. Because the children were randomly assigned to conditions, this study is an example of _____ research.
experimental
A researcher uses the experimental method to determine if texting while driving causes more accidents. Even if she includes an experimental and control group, it is still possible that a(n) blank________ can interfere with the outcome of her experiment
extraneous variable
A variable that is intentionally manipulated by a researcher using the experimental method is called a(n) blank___________ variable.
independent
An investigator gives the experimental group a sports drink and the control group a placebo. In this study, what the groups receive is the _____ variable.
independent
A positive correlation:
indicates that as one variable increases, the other variable increases.
In order to obtain _____, Dr. Ampur makes sure that every subject understands what the study will entail.
informed consent
Which is a measure of central tendency?
mode
A downward sloping scatterplot indicates:
negative correlation
The strength of a relationship is indicated by the _____ of the correlation coefficient.
numerical value
The scientific method allows researchers to collect empirical evidence. Which of the following terms is the best synonym for the word "empirical?"
objective
In a research study examining depressive symptoms, "the score an individual receives on the Beck Depression Inventory" is a(n) _____ definition for level of depression.
operational
Professor Gliserman is studying the effect of alcohol on response time. Professor Gliserman will likely find _____ between the two variables.
positive correlation
An upward sloping scatterplot indicates:
positive correlation.
If you were recruiting college students for a study, you could use a random number generator to select potential participants from your college student directory. With this method you would be using a(n) blank________ to avoid introducing bias into your research.
random sample
_____ refers to the consistency or stability of a measure.
reliability
The attributes of a(n) _____ sample mirror those of the population of interest.
representative
A subset of participants that is chosen to reflect the population of interest is called a(n):
representative sample
As part of his senior project, Noah is conducting a survey of eating attitudes and behaviors among young adults. Noah distributes questionnaires to 150 randomly selected students enrolled in lower-level psychology courses at his university. These students make up Noah's _____. Young adults in general constitute Noah's _____.
sample; population
A graph of the relationship between two uncorrelated variables would show a(n):
scattering of dots or scores with no line.
A ______ shows two variables combined as individual points on a graph.
scatterplot
Professor Rossi wants to represent the data she collected on age and income as single points on a chart. She can accomplish this using a:
scatterplot
Which of the following would be the most useful for showing a correlation between two variables?
scatterplots
NEGATIVE CORRELATION
scores that are negatively correlated are associated in such a way that one score falls as the other rises (as in the relationship between self-esteem and depression); correlation coefficient is negative
NEGATIVELY CORRELATED
scores that are negatively correlated are associated in such a way that one score falls as the other rises (as in the relationship between self-esteem and depression); correlation coefficient is negative
POSITIVE CORRELATION
scores that are positively correlated go up and down together (as with high school and college GPAs); correlation coefficient is positive
POSITIVELY CORRELATED
scores that are positively correlated go up and down together (as with high school and college GPAs); correlation coefficient is positive
In a typical experimental session, informed consent:
takes place before the experimental procedure begins.
Which research technique relies on the in-depth examination of an individual or small group?
the case study
Most students know that there is a link between studying and grades: as hours spent studying increase, test grades also increase. If an instructor analyzes the relationship between hours of study and test grades, which aspect of the correlation coefficient will tell her the strength of the relationship between the two variables?
the number value of the coefficient
