Hypotheses, variables and sampling Flashcards
What is a variable?
Anything that varies
What does a psychology experiment test? and what the use of experiments is.
The effect of one variable on another, is a test of difference. Allows researchers to establish cause and effect links
What does a correlational study test?
How strongly two variables are associated- describe the relationship between 2 variables
What is the IV and DV ?
IV- Variable manipulated by experimenter
DV- Outcome measured by experimenter
What is an experimental/alternate hypothesis and give an example?
For an experiment, the IV is predicted to affect the DV. EG There will be a significant number of words recalled from a list of 20 between ppts given 10 minutes to learn the list and those given 3 minutes to learn the list
What are co-variables and why are they used?
For a correlation, they are two variables that carry with each other and both are measured, neither one is set or controlled by the researcher- used when it’s hard/unethical to manipulate IV
V1&2- measured by researcher
What is an alternate hypothesis (Ha) for a correlation?
Where V1 is predicted to have an association with V2 EG There will be a significant negative correlation between a person’s age in years and the hours per week they use the internet
Tip for operationalising hypotheses?
How we will manipulate IV, and how we will measure DV (In a quantifiable way)
What is an extraneous variable?
Any variables that MIGHT affect the DV apart from the IV
What is a confounding variable?
Uncontrolled extraneous variables that have affected results
What are situational variables and how can we control them?
Variables in the research situation itself can affect the DV.
Can be controlled via pilot studies or standardisation
What are participant variables and how can we control them?
Variables from individual ppts and impact their performance
Controlled by randomisation to assume differences between ptts are balanced out across the conditions
What are order effects and how can we control them?
The order in which ppts carry out a task- occurs in research where a group of ppts are asked to carry out a task twice
Controlled with counterbalancing eg half the ppts complete the task in one and order and half complete the task in another order
What are demand characteristics and how do we control them?
Cues ppts might get that indicate purpose of research
Controlled by low levels of deception
What are researcher effects and how do we control them?
If a researcher knows the aims of the study and an expected outcome they many struggle to remain objective and reflect expectations
Controlled by standardised procedures
Give an example of a one-tailed hypothesis.
There will be a significant positive correlation between the attractiveness ratings of males and females in married couples
Give an example of a two-tailed hypothesis.
There will be a significant difference in memory recall between ppts who drink alcohol and ppts who don’t drink alcohol
or there will be a sig correlation..
Give an example of a null hypothesis (Ho) for an experiment and correlation
Exp- the consumption of alcohol will not significantly affect memory capacity
Correlation- There will be no significant correlation between the attractiveness ratings of females and males in married couples
Why is it important to have a representative sample?
It allows us to generalise our results to our target population as a representative sample is a group of ppts drawn from target population that is typical of that target population
What is sampling bias?
The sample becomes weighted due to an overrepresentation of one group- may come from volunteers
What is random sampling?
Sample , in which every member of the target population has an equal chance of being selected
Name one advantage and one disadvantage of random sampling
One advantage is that larger samples provide the best chance of an unbiased and presentation sample. This is because everyone has an opportunity to be chosen.
One disadvantage is that in psych the larger the target population the more difficult it is to sample randomly since compiling the original selection becomes impractical. Furthermore, gathering names can be difficult due to legal restrictions. For example, the Data Protection Act (1998) may limit the collection of a true random sample.
What is opportunity sampling?
Selecting ppts that are available at the time
Name one advantage and disadvantage of opportunity sampling.
One advantage is that the opportunity sample is quick, convenient and efficient. It is also ethical as the researcher can judge whether a ppt will likely be upset by the study.
One DA is that it may be unrepresentative as it’s biased. This is because it is only drawn from a small sector of the target pop the researcher can access and the researcher may only choose ppts who seem friendly and likely to help and ppts are only those who are willing to take part making them particularly helpful
What is volunteer sampling?
When volunteers consciously decided to become part of the study eg seeing an advert in a newspaper
One advantage and disadvantage of volunteer sampling
If ppts have volunteered after being fully informed of the nature of the research then this is very ethical as ppts decided themselves to be involved in the study. Volunteer samples allow access to a variety of pts and easy
However, if an ad is used then the sample will be biased by the fact not everyone in the target population will see the ad and not everyone who sees it will respond. AND USING VOLUNTEERS MAY BE SEEN AS BIAS AS RESEARCH SHOWS VOLUNTeers have different personality traits might be because they’re more motivated
What is stratified sampling?
Diving the target pop into important sub-categories to allow certain groups to be represented
One advantage and one disadvantage of stratified sampling
As a deliberate effort is made to identify and select the most important characteristics of the target sample will be representative which means credible conclusions can be drawn
However, identification of these sub-categories can be a source of sampling bias as the researcher may have preconceived ideas on relevant characteristics this means important subcategories will be excluded and it becomes less representative