Research methods Flashcards
What is an experiment?
A research method in which the researcher tries to control all variables other than the independent variable and the dependent variable; this allows the researcher to identify a cause-and-effect relationship between the IV and the DV.
What is a hypothesis?
A testable statement about the relationship between two variables: The independent variable and the dependent variable.
What is the independent variable?
The factor which will be varied or changed in an experiment to look for an effect on the other variable.
What is the dependent variable?
It is the outcome or effect we are measuring within the study.
What is a null hypothesis?
A hypothesis that exists and states that no variables affect any other variables.
How do you write a null hypothesis?
There is not going to be a significant difference in the “dependent variable” between “condition a” and “condition B” of the “independent variable”.
What is an alternative hypothesis?
The hypothesis the researcher tests by conducting a study and collecting data, which attempts to show the null hypothesis is not supported.
How do you write an alternative hypothesis?
It is predicted that there will be a significant difference in the “dependent variable” between the two conditions of the “independent variable”.
What are the different experimental methods?
- Laboratory experiment.
- Field experiment.
- Natural experiment.
What is a laboratory experiment?
- There is a high level of control of extraneous variables.
- There is an IV which is manipulated by the researcher and causes a change in the DV.
- They take place in a controlled environment, often a laboratory
What are some advantages of a laboratory experiment?
- Easy to replicate, because it is possible to recreate the same environment and the same procedures. So we can check the reliability of the results
- Researcher has control over the variables, so we are able to conclude that the IV is the cause of the DV
What are some disadvantages of a laboratory experiment?
- The setting is artificial. They often lack ecological validity, as the behaviour studied does not represent real life conditions. The results cannot be generalised to the natural environment of participants
- Participants may display demand characteristics, which means that they understand the aim of the study and act accordingly
What is a field experiment?
- This is conducted in a real life setting – for example, a school, hospital or subway.
- Takes place where the behaviour would normally occur.
- The experimenter still manipulates the IV to see the effect on the DV.
What are some advantages of a field experiment?
- Behaviour is more natural than laboratory experiment, as it takes place in the natural environment, so we have higher ecological validity.
- The participants do not know they are being studied, so they act naturally
What are some disadvantages of a laboratory experiment?
- Deception – participants do not always know they are taking part in research.
- Extraneous variables cannot be controlled in the natural environment, so we cannot be sure that the IV is the cause of the DV
What is a natural experiment?
- This is where the independent variable changes naturally (on its own). It is not manipulated by the researcher.
- For example, the effects of stress on families due to the recent recession. An experimenter cannot create this situation, it has occurred naturally and so they can study the effects of the IV.
What are some advantages of a natural experiment?
- Allows researchers to study variables that could not be manipulated (eg, the effect of gender or age on behaviour).
- There is some control over extraneous variables, so it is possible to see how the IV affects the DV.
What are some disadvantages of a natural experiment?
- The environment can be artificial and so there might be low ecological validity.
- Participants might be aware that they are being studied, so their behaviour will not be natural
What is experimental design?
How the participants are used in the conditions of an experiment.
What are the different types of experimental design?
- Independent groups.
- Repeated measures.
- Matched pairs.
What are independent groups?
Where two or more separate groups of participants are used in an experiment; each member of the pair takes part in a different condition.
What are some advantages of independent groups?
- There are no order effects because people only take part in one condition.
- Often, the same material can be used for the task in both conditions.
- Participants cannot work out the aim of the study because they only take part in one condition.
What are some disadvantages of independent groups?
- There are different people(participant variables) and the two conditions so that may be why the results are different.
- You need more people for the study. To get 10 in each group you need 20 people.
What are repeated measures?
When only one group of participants is used in an experiment; this group takes part in both conditions.
What are some advantages of repeated measures?
- The people in both conditions are the same, so there are no participant variables.
- You only need 10 people to get 20 results because each person produces two scores.
What are some disadvantages of repeated measures?
- There are order effects as people have to do two tasks.
- You may need to tasks (you cannot use the same list twice).
- Participants may work out the aim of the study because they take part in both conditions.
What are matched pairs?
Where people with similar qualities are grouped into pairs; each member of the pair takes part in a different condition. Their scores are counted as one person.
What are some advantages of matched pairs?
- Participant variables are reduced.
- There are no order effects.
- Often the same material can be used for the task in both conditions.
What are some disadvantages of matched pairs?
- Matching is difficult, time-consuming and not always successful.
- Some participant variables are still present.
What are order effects?
When a participants performance in the second condition of an experiment is affected because they have already done the first condition. They may do better because of practice or worse because of tiredness. This may happen in a repeated measures design.
What are participant variables?
The differences between the people who take part in the study. These may affect the results of an experiment that uses an independent groups design.
What are standardised procedures?
A set order of carrying out a study that is applied to all participants when necessary.
What are extraneous variables?
A variable that is not the IV but might affect the DV if it is not controlled.
How do you control extraneous variables?
- Instructions to participants.
- Randomisation.
What are instructions?
The written (or verbal) information given to participants during an experiment.
How do instructions affect how a participant behaves?
The information that is said or written for participants might affect the way they participate in the study and therefore their scores or performances - this could be an extraneous variable.
How should we write instructions?
- Briefing.
- Standardised instructions.
- Debriefing.
What should we include in the briefing?
- Encourage a person to agree to participate.
- Contains ethical information about consent, anonymity, the right to withdraw and so on.
What should we include in the standardised instructions?
These are clear instructions about exactly what the participant will have to do in the experiment.
What should we include in the debreifing?
- This explains the study in detail so that each participant is absolutely sure of the aim of the study.
- Ethical issues are also addressed again, especially the opportunity for the participant to withdraw their data if they feel unhappy about their performance.
What is randomisation?
Using chance to provide an order for a procedure.
How can the experimenter use randomisation?
- Each word has an equal chance of being selected first for the list and the experimenter left the final order of the words to chance.
- The researcher has to be sure that all participants are presented with the words in that same order.
How do you allocate participants to certain conditions?
- Random allocation.
- Counterbalancing.
What is random allocation?
When the researchers divide the participants and allocate them to certain groups using a random method.
How can the experimenter use independent groups with random allocation?
If 20 people are available for the study the experimenter can put 10 pieces of paper with ‘A’ on them and 10 into a bag with ‘B’. Each participant takes a piece of paper from the bag and that determines the condition they take part in.
How can the experimenter use independent groups with matched pairs?
Putting the letters for a pair in a bag (A and a) and getting one participant to select the letter. This is then repeated for every pair - the same goes for condition B.
How can the experimenter use independent groups with repeated measures?
They cant - they use counterbalancing.
How can the experimenter use counterbalancing with repeated measures?
Half of the participants complete condition 1 then condition two; the other half complete condition too then condition one. This will not completely get rid of order effects but it will share the effects equally between the two conditions.
What is the target population?
The large group of people that the researcher wishes to study.
What is a sample?
The small group of people who represent the target population and who are studied
What is a representative sample?
When the sample of participants is made up of people who have the same characteristics and abilities as the target population.
What are the sampling methods?
- Random sampling.
- Opportunity sampling.
- Systematic sampling.
- Stratified sampling.
What is random sampling?
Every member of the target population has an equal chance of being selected. You number papers and put them into a box, then you pull out papers and the person that corresponds to that number will participate.
What are the advantages of random sampling?
- Eliminates bias.
- Likely to be representative of the target population.
What are the disadvantages of random sampling?
- Time-consuming if there is a large target population.
What is opportunity sampling?
People who are members of the target population and are available and willing to take part in research. You ask people who are easily available to participate in your study.
What are the advantages of opportunity sampling?
- Convenient.
- Saves time and effort.
What are the disadvantages of opportunity sampling?
- It is not likely to be representative of the target population.
- There is a bias.
What is systematic sampling?
A specific system to pick sample members. Every (nth) member of the target population is selected for the sample.