1 Identify each of the following phrases as a theory, hypothesis, or observation.
a 20 out of 25 basketball players improved their free-throw shooting percentage.
b More positive reinforcement by the professor will improve test scores.
c Human interactions are best thought of in economic terms; our actions seek to maximize gains and minimize costs.
d “Chickens”come before“eggs.” e More people choose Car A over Car B.
f When giving names in a circle, people will not recall ones given just prior to theirs.
2 Which of the following descriptions is the clearest operational definition for the concept“vacation?”
a An extended period of recreation, especially when spent away from home.
b Release from obligation, business, or ordinary activity.
c A stretch of time set aside to relax or travel for pleasure.
d The number of days in a year a person spends not working and away from home.
3 A researcher has just begun to start to study the“tiny house”trend in home construction. Think of two researchable questions that line up with each of the three different goals of the researcher: description, correlation, and understanding.
4 Identify the independent and dependent variables in the following four studies.
a A psychologist is interested in the effects of vitamin E on physical endurance. One group of participants receives 20 units of vitamin E, another 60 units, and a third gets a placebo. Endurance is assessed by the length of time participants can ride a stationary bicycle. (Also, how many levels are there of the independent variable?)
Questions and Exercises 29
b A teacher evaluates the effectiveness of different educational programs on reading speed and comprehension.
c A social psychologist hypothesizes that attitude change will be greatest when people do not have sufficient justification to explain their counter- attitudinal behavior compared with when they do have sufficient justifi- cation. (Imagine a person opposed to watching a scary movie but who is compelled to do so by social pressure. In one condition, they are paid $1 as compensation and in the other $50.)
d An industrial psychologist hypothesizes that the amount of natural light in the work setting will increase productivity. For 15 days of a month, the blinds are drawn, and indoor lighting is the only source of light. For the other 15 days of the month, the shades are left open. Productivity is meas- ured by the number of widgets made.
5 Imagine an experiment investigating the effectiveness of different rewards used by parents to “potty train” their children. Identify several different types of quantitative and qualitative levels for the independent variable.
Also, describe how to use the technique of“holding constant”to control at least one potent extraneous variable.
6 Identify a confound affecting internal validity in the following four studies.
(Hint: Some studies may not be confounded.)
a An independent marketing company has been hired to assess people’s preference for A&W root beer versus Stewart’s root beer. To prevent bias, all of the test cans are covered with paper, with the letterAplaced on the A&W cans andBplaced on the cans of Stewart’s. The order is counterbalanced such that half of the participants experience A&W first and then Stewart’s and the other half experience the other order. The results show that the participants prefer A&W over Stewart’s by a 2:1 ratio.
b An experimental psychologist claims to have discovered an important cause of bizarre behavior. Laboratory mice are taught to discriminate between two geometric designs. The mouse is required to jump from a ledge through a trap door, which has one of the designs painted on it. If the mouse leaps through the door with the correct design, it lands on a table with food. If the wrong door is chosen, the mouse falls 3 ft onto a net. (Falling 3 ft onto a net may be fun for kids, but it is rather unnerving for a mouse.) Eventually all the mice in the study pick the door that has the correct design painted on it. A discrimination has been formed. To test the intelligence of each mouse, the researcher changes some aspects of the geometric designs so that they look much more alike than they did originally. Now the mice hesitate and many refuse to jump. To observe which door the mice will choose, the psychologist forces them to jump by
blasting a loud noise. Faced with such a difficult discrimination, the mice begin to exhibit unusual behavior. They run in circles, jump up and down, and fall into a catatonic state. It is concluded that the stress pro- duced by having to choose between two very similar stimuli when the consequences of the choice are extremely important leads to abnormal behavior.
c A particular stretch of highway is noted for an excessive number of traffic fatalities. The city council decides to reduce the allowable speed limit, since evidence from national statistics clearly shows that traffic fatalities are cor- related with speed limits. To make sure that the proper speed limit is observed, radar units are positioned every 5 miles along the highway.
Not only did accidents significantly decrease, but also because of the increased surveillance, more motorists were following the speed limit.
Obviously changing the speed limit has led to a decrease in accidents.
d Evidence shows that our reactions to pain are, in part, due to psycho- logical factors. A dentist offers headphones with the patient’s choice of music to listen to during procedures involving moderate discomfort.
Since some patients may prefer the novocaine, that option is also made available. Patients are not allowed to listen to musicanduse the anes- thetic. Patients are free to choose which method they want. At the end of the study, the dentist finds that those patients using the headphones reported less anxiety and less pain than those patients who opted for the novocaine. To address a potential confound, the dentist went back and checked records to see that the type of dental procedures was, on average, similar between the groups.
7 A popular theory of emotion asserts that we label our emotional states based on the perception of our own physiological arousal and the situation within which we find ourselves. However, one could question whether the presence of physiological arousal is really necessary. Maybe all that is required is the beliefthat we are aroused. A study is conducted with biological male under- graduates where 20 slides of different biological females are sequentially presented for 30 seconds each. The participant wears earphones and hears what isbelievedto be their own heart rate; but in fact, it is a recording. The participant hears an increase in heart rate for some slides and a decrease in heart rate for other slides. The assignment of heart rates to pictures is ran- dom and different for each of the numerous biological male participants involved in the study. The dependent variable is the participants’ ratings of attractiveness made after each slide. The psychologist finds that the females observed when the tape-recorded heart rate was high were per- ceived as more attractive than the females viewed during decreased heart rates. Therefore, belief in arousal influences perceptions of emotion. Does this experiment have a threat to internal validity?
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8 “Controlling extraneous variables”is to“generalizability” as:
a Independent variable is to dependent variable.
b Internal validity is to external validity.
c Correlational design is to experiment.
d Random sampling is to random assignment.
e Population is to sample.
9 Professors may exhibit a good deal of subjectivity when grading papers. For instance, some prefer title pages, while others do not. Suppose we conduct a study in which we obtain the grades for a paper submitted by everyone in class. Since this professor does not specify whether the assigned paper requires a title page, we are able to find a similar number of papers that do and do not have them. Our results show that the average grade for the “title-page” papers is higher than for papers not containing them.
Should we conclude that our professor prefers“title-page”papers? What other interpretation of the results can we make?
10 Which of the following means of assigning participants to two experimen- tal conditions in a psychological study represent“random assignment?” a Flipping a coin right before each participant is due to arrive at the lab.
b Looking at a students’ ID card and putting numbers that end in an odd number in one group and those that end in an even number in the other.
c Assigning students who signed up in class to the experimental condition and those that signed up online to the control.
d Asking each student to choose which color they prefer – those that choose “red” go to one condition and those that choose “blue” go to the other.
e Asking participants their age. Even ages go to one group, and odd to the other.
11 Which of the following selection procedures represent the“random sam- pling”of students at a university campus?
a Standing outside of the cafeteria and asking every third person who walks in if they will participate in a study.
b Asking the registrar to give us the name of every twentieth person going alphabetically through the university enrollment list.
c Sending out an email to the entire campus asking for volunteers.
d Getting permission from our professors to stand up in front of class to ask our fellow classmates.
e Cutting out each name from the university directory, putting them into a basket, and then blindly drawing names.
12 For each of the following research questions, design a study that addresses the question with a controlled experiment. Redesign the study using a cor- relational methodology. (Hint: It is possible that one or more questions cannot be investigated by controlled experimentation.)
a Is there a relation between pain and anxiety? (For the experimental design, pain is the independent variable.)
b Is there a relation between how often a person exercises and resting heart rate?
c Is there a relation between need for achievement and hours worked per week?
d Do children who attend preschool day care show better social skills in first grade?
Questions and Exercises 33
Part 2
Descriptive Statistics