AP Psychology › Construction, Reliability, & Validity of Testing Methods
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.
In this experiment, what is the independent variable?
Students' receipt of the smart pill vs. the sugar pill
Group A versus Group B
The number of words recited
Reciting the list in any order
Five minutes given to study the list
The independent variable is what the researcher manipulates in order to test his or her hypothesis. In this experiment, Dr. Smart gave one group the smart pill and the other group a sugar pill in order to evaluate the smart pill's effect on student memorization.
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.
In this experiment, what is the dependent variable?
Number of words recited correctly
Students' receipt of the smart pill vs. the sugar pill
Group A vs. Group B
Reciting the list in any order
Five minutes to study the list
The dependent variable is the item actually being measured or analyzed the support or reject the hypothesis. The dependent variable measures the effect of the independent variable.
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.
Group A is the __________.
experimental group
control group
independent variable
tester group
placebo group
The experimental group is the group assigned to measure the effect of the independent variable. Students in Group A were given the smart pill, and thus their results will be analyzed to measure the effect it had on student memorization.
Which of the following is not a common difficulty associated with the double-blind study protocol?
Double-blind studies make subsequent meta-analysis of the results more difficult, as it becomes harder to separate the results of the study from the expectations of the hypothesis
If a medical treatment is discovered to be very effective, it might be unethical to continue withholding treatment from the control group
Keeping researchers blind to the groupings usually involves significant expenses or time investment that studies often cannot afford
Researchers may have to settle for a less powerful treatment effect, as a more powerful one would "tip them off" to which group was being treated
Clinical protocols may make a double-blind methodology impractical (i.e. in treatment effects involving invasive surgery vs. no invasive surgery, where scars would be visible)
In a double-blind protocol, both the research participants and the researchers engaging in the study are unaware of which participants are in the control group and which are in the experimental group. This actually makes subsequent meta-analysis of the double-blinded results easier, as a correctly applied double-blindness will remove any of the researcher's biases from the results.
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.
Group B is the _________.
control group
experimental group
independent variable
tester group
placebo group
The control group is the group assigned to provide a comparison to the experimental group’s results, in order to measure the effect of the independent variable. Students in Group B were given a sugar pill instead of the smart pill to measure the effect on how many words students could properly recite.
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.
What is Dr. Smart’s null hypothesis?
There is no significant difference between the number of correct words recited by Group A and Group B.
There is a significant difference between the number of correct words recited by Group A and Group B.
The number of the words recited by Group A will be greater than or equal to the number of words recited by Group B.
The number of the words recited by Group B will be less than the number of words recited by Group A.
The smart pill works.
The null hypothesis suggests that the independent variable has no effect in the experiment. If Dr. Crawford’s null hypothesis is supported, then her smart pill has virtually no effect on student memorization. The goal is to reject the null hypothesis with results from the experiment.
A sample of players on a baseball team are chosen to be drug tested. Which of the following methods could league officials use to ensure that the players are randomly selected?
Choosing to test every fifth player on an alphabetically-listed roster
Choosing to test every player over thirty years of age
Choosing to test every player with over ten home runs
Asking for volunteers and then testing those players
Choosing to test all of the pitchers on the team
Random selection allows all of the players on the team to have an equal chance of being chosen for testing. Choosing to test only players of a certain age or position, or only testing those that volunteer or have reached a certain statistical benchmark, would exclude a number of the players on the roster from having a chance to be chosen.
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.
What sort of experimental design is this?
Independent measures
Repeated measures
Separate variables
Independent variables
Counterbalancing method
Independent measures designs describe an experiment in which there are two or more separate groups. In Dr. Crawford’s experiment, the two groups are the students in Group A and Group B. The students do not overlap groups, and are only exposed to one of the two conditions during the experiment.
Dana is participating in a study that asks her to press a red button every time the computer screen in front of her shows a letter X.
The computer screen shows a letter "T." Dana presses the red button. Dana's response is considered to be which of the following?
False alarm
Miss
Hit
Correct rejection
None of these
A false alarm is a response that says the target stimulus (in this case, the letter X) has been detected when that stimulus is not present.
After much success with her initial experiments (i.e. Groups A and B) and pilot test, Dr. Crawford wanted to further test the effects of a “smart pill." She recruited a new group of twenty students, Group C, for this next experiment. In the first trial, she gave the students the smart pill, and then waited five minutes to give them the list of forty words. Students were instructed to memorize the list in any order and were given five minutes to study it. The students were then asked to verbally recite all of the words they could remember within three minutes. One week later, Dr. Crawford repeated the experiment with the same group and same list of words. However, on the second trial, students were given the sugar pill instead of the smart pill.
On the first trial, students from Group C recalled an average of seventeen words. On the second trial, students recalled an average of twenty words.
Which of the following experimental designs best describes this particular study?
Repeated measures
Independent measures
Separate variables
Independent variables
Counterbalancing method
The students in Group C undergo the experiment two separate times, and experience both conditions. No other students than the 20 in Group C are used in this experiment. They act as both the control group and the experimental group.