Research Methods Flashcards
Why is psychology a science?
Because it employs scientific method
What is scientific method?
A systematic approach for planning, conducting and reporting research which involves collecting empirical evidence.
What is empirical evidence?
Data collected directly from observation or experimentation
Why is scientific method used?
It helps to ensure that data collected is accurate, reliable and Th results obtained are valid.
What are the steps in psychological research?
- Identify a research problem.
- Write a hypothesis.
- Design the method.
- Collect data.
- Analyse Data.
- Interpret Data.
- Report findings.
What is an experiment used for? What is an experiment?
To test the cause and effect relationships between two or more variables under controlled conditions. In an experiment, a variable is manipulated.
What is a variable? How do experiments relate?
Any factor that can change in amount or type over time. Every experiment includes at least one independent and one dependent variable.
What is an independent variable? An example?
It is the variable that is systematically manipulated in order to assess its effect on the participants’ responses. The iv is often the only difference between the control and experimental groups. When testing the effects of caffeine on sleep quality, the IV is caffeine. One group would be given it and the other wouldn’t.
What is the dependent variable? An example?
It shows the effects of the independent variable. The changes in the DV are caused by the IV. It is the variable that is measured or the results. Eg. When testing the effect of caffeine on sleep quality, the DV is sleep quality.
What is the simplest type of experiment often like?
It uses one IV (on two levels) and measures one DV. The two IV levels are often the experimental and control groups.
What is the experimental condition?
The one where the IV is present. An experiment can contain two experimental groups only.
What is the control condition?
Where the IV is absent. It provides a standard or basis of comparison for the experimental condition.
Why do variables need to be operationalised? What variables need to be operationalised?
The variables need to be stated in a way that explains how they will be observed or measured. Both variables need to be operationalised.
How would a variable be operationalised?
When testing the effect of caffeine on sleep quality:
IV: caffeine— 6 cups of strong coffee a day or 30mg of caffeine in 24 hours
DV: sleep quality— sleep quality as measured by the number of hours slept in a night.
What is a hypothesis?
An educated guess or testable prediction about the relationship between two or more variables.
What are the main features of a hypothesis? (8)
- It is testable (the variables can be reliably measured, observed and manipulated)
- it is based on logical reasoning, theory or past research findings.
- it is expressed clearly
- it is usually written as a single sentence
- one hypothesis per IV
- it includes the population
- it has a direction
- it includes both the IV and DV (which don’t have to be operationalised)
What are participants?
People used in an experiment
What is a population?
The larger group from which the sample is drawn. In scientific research the population does not refer to all the people in a country or the world but a particular group that has one or more characteristics in common.
What is the sample?
The subset of the larger group (population) chosen for the study. It is always smaller than the population.
How are participants selected for a study?
Using sampling or selection.
What should a sample be? How should this be achieved?
It should be representative of the population. Relevant participant characteristics of the population that may influence the study must be reflected. In order to achieve this random sampling must be used.
What is random sampling? How can it be done? Why is it done?
It occurs when every member of the population has an equal chance of being selected as a participant in the study (and the selection of one participant doesn’t affect the selection of another). A random number generator or table of random numbers or some other lottery type process is used to do this. It ensures that the sample is representative of the population. If a sample isn’t random, it’s biased.
What are advantages of random sampling?
- The results obtained are likely to be representative of the population.
- the results can be generalised to the population.
What are disadvantages of random sampling?
- it is not always necessary or desirable to use it
- time consuming and can be expensive
- large sample is necessary
What is convenience sampling or opportunistic sampling?
In some studies it is not convenient, suitable or possible to obtain a representative sample (obtained through random sampling). A convenience sample involves selecting participants who are readily available whiteout employing random sampling.
What are advantages of convenience sampling?
- widely used, particularly in pilot research to gain a preliminary indication of responses before conducting the actual study
- quick, easy and inexpensive
- often considered to be adequate when investigating mental processes that are assumed to be similar in ‘normal’ people
What are disadvantages of convenience sampling?
- Most times convenience sampling produces a biased sample, because they only use participants available at a particular time or location.
- a convenience sample is not representative of the target population
- the data may be misleading and the results cannot be generalised to the entire population
- has low external validity
When does Stratified Sampling occur?
When the population is divided into distinct groups, or “strata” and then Samples of proportionate size are drawn from within each strata.
What is random stratified sampling?
The sample is drawn randomly from the groups. This is most accurate.
What is stratified sampling?
The sample is not drawn randomly from groups. That is, the known groups in a population are represented in the same proportions in the sample.
What are examples of stratified sampling? (2)
- the sample is truly representative of the population
* the sample is unbiased
What are disadvantages of stratified sampling? (3)
- Very time consuming
- difficult to achieve
- not often used
What is participant allocation? What’s important when allocating?
The allocating of participants of the sample into different groups involved in a research study. To keep both groups as similar as possible to ensure nothing else affects the DV.
What is random allocation? Why is it used?
This means that every participant in the experiment has an equal chance of being in any of the groups used. It is an important means of experimental control. The participants are allocated to the experimental and control groups and the purpose is that the groups are as similar as possible.
What are the experimental designs? (3)
- Repeated measures design
- matched-participants design
- independent groups design
What is the repeated measures design?
Each participant is in the control and experimental groups. They are tested at least twice.
What are advantages of the repeated measures design? (1)
• EVs and potential CVs are minimised because the same participant is being used in both conditions
What are disadvantages of the repeated measures design? (5)
- order effect occurs and counter balancing is required to balance out the order effect
- participant demand characteristics may not be kept constant eg. Guessing the purpose of the experiment and behaving accordingly
- participant attrition occurs
- time consuming per participant and many drop out before completed
- can’t always use this method, depending on the nature of the IV
How does matched-participants design work? Who is best suited to this kind of experiment?
Pairs of participants, similar in key characteristics that can influence the IV, are randomly allocated, one to the control and one to the experimental. Often pre-testing is done to determine characteristics that need to be matched. Identical twins are great subjects.