AIMS, HYPOTHESIS,AND VARIABLES
Define the confounding variable
Confounding variables: any variable other than the IV that may have an effect on the DV so we cannot be sure of the true source of changes to the DV. Confounding variables vary systematically with the IV
Name the four types of experiments
Quasi, field, natural, laboratory
Name five types of sampling method
Random sampling, stratified, opportunity, systematic, volunteering
Give two weaknesses of random sampling
It may still contain volunteer bias. Asking for volunteers may attract a certain 'profile' of a person, that is, one who is helpful, keen and curious (which might affect how far findings can be generalized).
It may not be a representative of the sample. This is because not everyone might have the same access to the notice put out by the researcher. For example, if a researcher puts a notice board in a community center, people who come there once a month will probably not see it.
Evaluate independent group
Order effects are not a problem. The participants only do the task once. This means they won't benefit from the practice
It is less time consuming to collect the data if all the conditions of the experiment are being conducted simultaneously.
Define investigator
Investigator Effects: any effect of the investigator's behaviour (conscious or unconscious) on the research outcome (the DV). This may include everything from the design of the study to the selection of, and interaction with, participants during the research process
Evaluate natural experiment
have high validity. This is because variables naturally occur and are related to everyday life. This presents an opportunity to conduct an experiment on something that would be unethical to artificially create. However, it relies on infrequent natural events. This means opportunities for this kind of research is rare. This reduces the usefulness of this experimental method
Evaluate random sampling
There is no bias. Every person in the target population has an equal chance of being selected. So the sample is more representative.
It has less effort, more value collection. This is because researchers simply need to pick names out of a hat. Yet, it is still more representative than other methods such as volunteering
Selected participants may refuse to take part. This means you could end up with a volunteering-like sample. This means your sample may not be representative of your target population
Give two disadvantages of stratified sampling
It is very time-consuming. It may take a while to identify proportions of subgroups and then recruit participants. This discourages researchers from using this method.
Additionally, the identified strata cannot reflect all the ways that people are different, so a complete representation of the target population is not possible.
One strength is that participant variables are controlled. Each participant is compared against themselves rather than other people. This enhances the validity of the results.
Fewer participants are needed. In an independent groups design, you need twice as many participants to get the same number of data items. This makes repeated measures less expensive.
Order effects occur when participants are tested twice. The order in which they do the tasks may make a difference, e.g. a practice effect. This affects the validity of the results.
A disadvantage to the repeated measure design is that it may not be possible for each participant to be in all conditions of the experiment (i.e. time constraints, location of the experiment, etc.).
Define hypothesis
A clear precise, testable statement that states the relationship between the variables to be investigated. Stated at the outset of any study
Evaluate Quasi experiment
Quasi-experiment: means members cannot be randomly allocated to different variables. This is because the IV depends on who they are. This creates confounding variables. However, they are usually carried out in controlled conditions. This means the researcher can control EVs. Therefore, cause and effect can be established.
Give two strengths of stratified sampling
It avoids researcher bias. This is because once the target population has been sub-divided into strata, the participants that make up the number are randomly selected and beyond the influencer of the researcher.
This method produces a representative sample because it is created to accurately reflect. This means that generalization of findings becomes possible
Give two strengths of opportunity sampling
It is easy quick and cheapy to carry out because you simply choose people who are nearby. This makes the method less expensive
Secondly, because they are readily available, there is no need to ask for consent about whether they want to participate in the experiment. This saves time and ensures it's ethical.
Evaluate matched pairs
One strength is that participants only take part in a single condition so order effects are less of a problem
There are fewer participant variables. This is because those taking part are matched on a variable that is important for the experiment. This enhances the validity of the results.
What is the difference between an aim and a hypothesis
Aims are general statements about what is being investigated while hypotheses are clear, precise statements that predict the outcome of the investigation.
Evaluate laboratory experiment
Lab experiment: have low ecological validity. This is because they do not reflect everyday life. Therefore, participants change their behavior which reduces the validity. Which means data from the experiment cannot be generalized to the wider world. On the other hand, one strength is that standardized procedures can be used. This means the study can be replicated by other psychologists. This can help in testing the validity of results.
Give two weaknesses of opportunity sampling
The sample is unrepresentative of the target population as it is drawn from a very generalized specific area, so the findings cannot be generalized.
There is researcher bias. This is because the researcher has complete control of the selection of participants, and for instance, may avoid people based on how they look.
Give two strengths of systematic sampling
There is no researcher bias. This is because the researcher has no say over who is selected. This makes it more representative.
It is also usually fairly representative. For example, it would be possible, but quite unlucky, to get an all-male sample through systematic sampling.
1. Independents Group: Participants are allocated to different groups where each group represents one experimental condition
2. Repeated measures: All participants take part in all conditions of the experiment
3. Matched pairs: Pairs of participants are first matched on the same variable(s) that may affect the DV. Then one member of the pair is assigned to condition A and the other to condition B
What is 'experimental method'?
Involves the manipulation of an independent variable to measure the effect on the dependent variable.
Evaluate field experiment
Field experiments are often more realistic. This is because participants are not aware they are being studied. This enhances the validity of the results. However, there may be ethical issues. This is because participants don't know they are being studied. Therefore, participants cannot give their informed consent.
Give two weaknesses of systematic sampling
It may still be biased. The sample may consist of on particular group of people. This decreases the representativeness.
There is a possibility when researchers are choosing, it may coincide with a periodic trait. For example, a certain religious community in the target population may not be present because they've gone away to celebrate a holiday in their home countries.
Give two advantages of volunteering sampling
There is no researcher bias. This is because the researcher has no say over who is selected since participants are 'self-selected'. This makes it more representative.
It requires minimal effort from the researcher since volunteers are approaching the researcher. This makes it less time-consuming than other forms of sampling.
Define the extraneous variable
Extraneous variables: any variable other than the IV that may have an effect on the DV if it is not controlled . EVs are essentially nuisance variables that do not vary systemically with the IV