7.2: Experimental designs Flashcards
Participants in an experiment were shown a film of a robbery.
The participants were then divided into two groups.
One group was interviewed using a standard interview technique and the other group was interviewed using the cognitive interview technique.
All participants were then given an ‘accuracy score’ (out of 20) based on how closely their recall matched the events in the film (20 = completely accurate, 0 = not at all accurate).
The results of the experiment are that the median for the standard interview was 10 and the median for the cognitive interview was 15.
The experiment used an independent groups design.
Explain how this study could have been modified by using a matched pairs design (4 marks)
The researcher needs to ensure that the 2 groups are matched for key variables
Participants in an experiment were shown a film of a robbery.
The participants were then divided into two groups.
One group was interviewed using a standard interview technique and the other group was interviewed using the cognitive interview technique.
All participants were then given an ‘accuracy score’ (out of 20) based on how closely their recall matched the events in the film (20 = completely accurate, 0 = not at all accurate).
The results of the experiment are that the median for the standard interview was 10 and the median for the cognitive interview was 15.
The experiment used an independent groups design.
Explain how this study could have been modified by using a matched pairs design (4 marks).
The researcher needs to ensure that the 2 groups are matched for key variables.
Example
For example, any that might reasonably be expected to affect memory in this situation
Participants in an experiment were shown a film of a robbery.
The participants were then divided into two groups.
One group was interviewed using a standard interview technique and the other group was interviewed using the cognitive interview technique.
All participants were then given an ‘accuracy score’ (out of 20) based on how closely their recall matched the events in the film (20 = completely accurate, 0 = not at all accurate).
The results of the experiment are that the median for the standard interview was 10 and the median for the cognitive interview was 15.
The experiment used an independent groups design.
Explain how this study could have been modified by using a matched pairs design (4 marks).
The researcher needs to ensure that the 2 groups are matched for key variables.
For example, any that might reasonably be expected to affect memory in this situation, such as what?
For example, any that might reasonably be expected to affect memory in this situation, such as eyesight, age or intelligence
Participants in an experiment were shown a film of a robbery.
The participants were then divided into two groups.
One group was interviewed using a standard interview technique and the other group was interviewed using the cognitive interview technique.
All participants were then given an ‘accuracy score’ (out of 20) based on how closely their recall matched the events in the film (20 = completely accurate, 0 = not at all accurate).
The results of the experiment are that the median for the standard interview was 10 and the median for the cognitive interview was 15.
The experiment used an independent groups design.
Explain how this study could have been modified by using a matched pairs design (4 marks).
The researcher needs to ensure that the 2 groups are matched for key variables.
For example, any that might reasonably be expected to affect memory in this situation, such as eyesight, age or intelligence.
What should all participants be assessed for?
All participants should be assessed for the key variables
Participants in an experiment were shown a film of a robbery.
The participants were then divided into two groups.
One group was interviewed using a standard interview technique and the other group was interviewed using the cognitive interview technique.
All participants were then given an ‘accuracy score’ (out of 20) based on how closely their recall matched the events in the film (20 = completely accurate, 0 = not at all accurate).
The results of the experiment are that the median for the standard interview was 10 and the median for the cognitive interview was 15.
The experiment used an independent groups design.
Explain how this study could have been modified by using a matched pairs design (4 marks).
The researcher needs to ensure that the 2 groups are matched for key variables.
For example, any that might reasonably be expected to affect memory in this situation, such as eyesight, age or intelligence.
All participants should be assessed for the key variables and for each person in one condition, what should the researcher do?
All participants should be assessed for the key variables and for each person in one condition, the researcher should assign a ‘matched’ person in the other condition
In an experiment, researchers arranged for participants to complete a very personal and embarrassing questionnaire in a room with other people. Each participant was tested individually. The other people were confederates of the experimenter.
In condition 1: the confederates completed the questionnaire.
In condition 2: the confederates refused to complete the questionnaire and asked to leave the experiment.
The researchers tested 15 participants in condition 1, and 15 different participants in condition 2.
The researchers recorded the number of participants who completed the questionnaire in each condition.
For this study, the researchers had to use different participants in each condition and this could have affected the results.
Outline one way in which the researchers could have addressed this issue (4 marks)
The researchers could have addressed this issue with random allocation of participants to each condition
In an experiment, researchers arranged for participants to complete a very personal and embarrassing questionnaire in a room with other people. Each participant was tested individually. The other people were confederates of the experimenter.
In condition 1: the confederates completed the questionnaire.
In condition 2: the confederates refused to complete the questionnaire and asked to leave the experiment.
The researchers tested 15 participants in condition 1, and 15 different participants in condition 2.
The researchers recorded the number of participants who completed the questionnaire in each condition.
For this study, the researchers had to use different participants in each condition and this could have affected the results.
Outline one way in which the researchers could have addressed this issue (4 marks).
The researchers could have addressed this issue with random allocation of participants to each condition.
How could this be done?
This could be done as each participant is assigned to a number or identified by name
In an experiment, researchers arranged for participants to complete a very personal and embarrassing questionnaire in a room with other people. Each participant was tested individually. The other people were confederates of the experimenter.
In condition 1: the confederates completed the questionnaire.
In condition 2: the confederates refused to complete the questionnaire and asked to leave the experiment.
The researchers tested 15 participants in condition 1, and 15 different participants in condition 2.
The researchers recorded the number of participants who completed the questionnaire in each condition.
For this study, the researchers had to use different participants in each condition and this could have affected the results.
Outline one way in which the researchers could have addressed this issue (4 marks).
The researchers could have addressed this issue with random allocation of participants to each condition.
This could be done as each participant is assigned to a number or identified by name.
What happens to the numbers or names?
The numbers or names are placed into a random number generator
In an experiment, researchers arranged for participants to complete a very personal and embarrassing questionnaire in a room with other people. Each participant was tested individually. The other people were confederates of the experimenter.
In condition 1: the confederates completed the questionnaire.
In condition 2: the confederates refused to complete the questionnaire and asked to leave the experiment.
The researchers tested 15 participants in condition 1, and 15 different participants in condition 2.
The researchers recorded the number of participants who completed the questionnaire in each condition.
For this study, the researchers had to use different participants in each condition and this could have affected the results.
Outline one way in which the researchers could have addressed this issue (4 marks).
The researchers could have addressed this issue with random allocation of participants to each condition.
This could be done as each participant is assigned to a number or identified by name.
The numbers or names are placed into a random number generator.
What happens to the first participant drawn?
The first participant drawn is assigned to condition 1
In an experiment, researchers arranged for participants to complete a very personal and embarrassing questionnaire in a room with other people. Each participant was tested individually. The other people were confederates of the experimenter.
In condition 1: the confederates completed the questionnaire.
In condition 2: the confederates refused to complete the questionnaire and asked to leave the experiment.
The researchers tested 15 participants in condition 1, and 15 different participants in condition 2.
The researchers recorded the number of participants who completed the questionnaire in each condition.
For this study, the researchers had to use different participants in each condition and this could have affected the results.
Outline one way in which the researchers could have addressed this issue (4 marks).
The researchers could have addressed this issue with random allocation of participants to each condition.
This could be done as each participant is assigned to a number or identified by name.
The numbers or names are placed into a random number generator.
The first participant drawn is assigned to condition 1, the second where?
The first participant drawn is assigned to condition 1, the second to condition 2
A stratified sample of participants were shown a tray containing 30 unrelated items for 30 seconds, after which time the tray was removed from sight. Half the participants were made moderately anxious, by wearing fake electrodes, which they were told would give them electric shocks for answers they got wrong. The other participants had low anxiety levels, through being told that the fake electrodes were merely monitoring bodily processes. Participants were instructed to recall as many items as possible.
The experimental design was an independent groups design.
Explain one strength and one weakness of this experimental design in the context of this study (4 marks)
A strength of the independent groups design is that order effects do not occur
A stratified sample of participants were shown a tray containing 30 unrelated items for 30 seconds, after which time the tray was removed from sight. Half the participants were made moderately anxious, by wearing fake electrodes, which they were told would give them electric shocks for answers they got wrong. The other participants had low anxiety levels, through being told that the fake electrodes were merely monitoring bodily processes. Participants were instructed to recall as many items as possible.
The experimental design was an independent groups design.
Explain one strength and one weakness of this experimental design in the context of this study (4 marks).
A strength of the independent groups design is that order effects do not occur, why?
A strength of the independent groups design is that order effects do not occur, because they would in a repeated measures design, where participants encounter a learning or fatigue effect by performing the procedure more than once
A stratified sample of participants were shown a tray containing 30 unrelated items for 30 seconds, after which time the tray was removed from sight. Half the participants were made moderately anxious, by wearing fake electrodes, which they were told would give them electric shocks for answers they got wrong. The other participants had low anxiety levels, through being told that the fake electrodes were merely monitoring bodily processes. Participants were instructed to recall as many items as possible.
The experimental design was an independent groups design.
Explain one strength and one weakness of this experimental design in the context of this study (4 marks).
A strength of the independent groups design is that order effects do not occur, because they would in a repeated measures design, where participants encounter a learning or fatigue effect by performing the procedure more than once.
A weakness of the independent groups design
A weakness of the independent groups design is that only one piece of data is generated by each participant
A stratified sample of participants were shown a tray containing 30 unrelated items for 30 seconds, after which time the tray was removed from sight. Half the participants were made moderately anxious, by wearing fake electrodes, which they were told would give them electric shocks for answers they got wrong. The other participants had low anxiety levels, through being told that the fake electrodes were merely monitoring bodily processes. Participants were instructed to recall as many items as possible.
The experimental design was an independent groups design.
Explain one strength and one weakness of this experimental design in the context of this study (4 marks).
A strength of the independent groups design is that order effects do not occur, because they would in a repeated measures design, where participants encounter a learning or fatigue effect by performing the procedure more than once.
A weakness of the independent groups design is that only one piece of data is generated by each participant, so what?
A weakness of the independent groups design is that only one piece of data is generated by each participant, so twice as many participants are needed as with a repeated measures design
A psychologist wanted to test the effects of biological rhythms on the ability to solve maths problems. She used random sampling to form two groups each of 20 students.
She tested one group on one set of maths problems at 3 am in the morning. The other group were tested on another set of maths problems at 3 pm in the afternoon. She found that performance of the group tested at 3 pm was significantly better than the group tested at 3 am.
When submitted for peer review the paper was rejected because of serious design problems.
Explain one problem with the design of this study and suggest ways of dealing with this problem (4 marks)
One problem with the design of this study is random sampling - The 3pm group might simply have been better at maths than the 3am group
