Research Methods - Scientific Methods Flashcards
Aim
An aim is a precise statement about the purpose of the study and what it intends to find out. The aim should include what is being studied and what the study is trying to achieve.
Hypothesis
A hypothesis is a specific, testable statement about the expected
outcome of a study. The hypothesis should also be operationalised.
Parts of a hypothesis
The first part of a hypothesis that needs addressing is whether or not
the study predicts causation or correlation.
Correlation: The researcher predicts a relationship between two
variables being investigated.
Causation: The researcher predicts a difference in the Dependent Variable (DV) because of the manipulation of an Independent Variable (IV).
Differences in the DV resulting from manipulation of the IV are known as significant differences if it has been statistically shown using inferential statistics that the differences are highly unlikely to be due to chance.
Types of hypothesis
Null Hypothesis = This states that the IV will have no effect on the DV.
Alternative Hypothesis = This predicts that the IV will have an effect on the DV.
The alternative hypothesis falls into one of two categories.
Non-Directional Hypothesis = This DOES NOT state the direction of the predicted differences between conditions.
Directional Hypothesis = This DOES state the direction of the predicted difference between conditions.
How to know whether to use a directional or non-directional hypothesis
The decision as to whether to use a directional hypothesis or non- directional hypothesis is based on whether there is previous research in the field. If there is, we use a directional hypothesis, if not, we use a non-directional hypothesis. This is because previous research will enable us to predict which direction the results are likely to go in.
Pilot studies
Pilot studies are small-scale investigations conducted before research. They are useful because they can help to identify whether there needs to be any modifications in the design of the planned study. They also help to determine whether it would be feasible and worthwhile to conduct a full- scale study.
Target population
target population is used to describe the group who researchers are studying and want to generalise their results to.
Random sampling
Random sampling is when every member of the target population has the same chance of being selected. The easiest way to do this is to place all names from the target population in a hat and draw out the sample required.
Advantages and disadvantages of random sampling
Advantages
The sample is likely to be representative and therefore results can be
generalised to the target population.
Disadvantages
It is sometimes difficult to get full details of a target population from which to select a sample. Additionally, not all members of the target population who are selected to take part will be available or willing to take part, making the sample unrepresentative.
Time consuming with larger sample
Systematic sampling
Systematic sampling is a sampling technique where participants are
selected by taking every Nth person from a list.
Advantages and disadvantages of systematic sampling
Advantages
Systematic sampling is far simpler than random sampling.
Disadvantages
The process of selection can interact with a hidden periodic trait within the target population. If the sampling technique coincides with the periodicity of the trait, the sampling technique will no longer be representative.
Stratified sampling
Stratified sampling involves classifying the target population into categories and then randomly choosing a sample that consists of participants from each category in the same proportions as they appear in the target population.
Advantages and disadvantages of stratified sampling
Advantages
The strength of stratified sampling is that all groups within a target population are included, therefore the sample should be representative of the target population.
Disadvantages
Stratified sampling can be very time consuming as the categories have to be identified and calculated. If you do not have details of all the people in your target population you would struggle to conduct a stratified sample.
Opportunity sampling
Opportunity sampling involves selecting participants who are readily
available and willing to take part.
Advantages and disadvantages of opportunity sampling
Advantages
This is the easiest and most practical method of ensuring large samples.
Disadvantages
There is a high chance that the sample will not be representative of the target population. Sometimes people feel obliged to take part in research even when they do not really want to, this is unethical.
Volunteer sampling
Volunteer sampling involves people self-selecting to participate in a study. The researcher will usually advertise for people to take part in their research.