Aims, hypothesis tests, variables, sampling, pilots, Flashcards
What is experimental method?
While all other variables are held constant, one variable is manipulated and the effect of this on another variable is measured
What is non experimental method?
Researchers collect data without intervening or introducing treatments.
What is an aim?
A general statement of the direction of the study and what the research intends to investigate.
What is a hypothesis?
A clear, precise, testable statement that states the relationship between the variables to be investigated.
What is a directional hypothesis?
States the direction or difference of relationship.
What is a non-directional hypothesis?
States the relationship exists, but not the direction or difference.
What is a null hypothesis?
States the two variables are not related.
When are different hypothesis used?
If prior research- directional, if no prior research- non-directional.
What are the two levels of the IV?
Experimental condition and control condition.
What is operisationalisation of variables?
makes them measurable or countable
What is a pilot study?
A small-scale trial run of the actual investigation
What is the purpose of a pilot study?
-Identify design flaws, time and cost.
-To test how effective the instructions are.
-To avoid the floor effect.
What is the floor effect?
When a task is so difficult that all scores are very low
Advantages of pilots?
-Increases research quality.
-Helps estimating time/resources.
-Collects preliminary data.
Limitations of pilot studies?
-Requires extra resources.
-Doesn’t guarantee success.
-Small sample size.
What is a sample?
A subset of the population that can be generalised
What is the population?
the group the researcher is studying.
What is random sampling?
everyone in the population has an equal chance of being studied.
-put everyone’s names in a random name generator.
Advantages of random sampling?
Unbiased.
Disadvantages of random sampling?
- Difficult to ensure everyone is available
- Some people might not want to take part in the study
- There can be bias in that there may be more of one group than the other, such as more male soldiers than female
What is opportunity sampling?
Taking a sample of people who are available at the time that the study is being carried out and fit the criteria of the research.
Advantages of opportunity sampling?
quick, easy inexpensive?
Disadvantages of opportunity sampling?
Unlikely to provide a representative sample
Highly dependent on individual researcher
What is volunteer sampling?
Involves participants selecting themselves to be part of the sample.
-Can be in response to an advert.
Advantages of volunteer?
- More ethical as they chose to take part
- Volunteers are likely to be interested.
- Easy.
Disadvantages of volunteer?
Takes long time to get sufficient numbers
- Volunteer bias- people are one type of personality (extroverted and outgoing). This affects generalisation.
What is stratified sampling?
Dividing the population into subgroups then selecting a sample from each of these groups, so in the same proportions.
Advantages of stratified sampling?
- Each group is represented, so conclusions can be drawn
- Efficient to ensure representation from each group
Disadvantages of stratified?
Time consuming, can’t guarantee will be representative.
What is systematic sampling?
The required elements are chosen at regular intervals from an ordered list
Advantages of systematic?
-Objective so avoids bias.
-Easy to do for large populations.
Disadvantages of systematic?
A sampling frame is needed
It can introduce bias if the sampling frame is not random or accurate.
