aims, hypotheses and variables

i like research methods

what is the definition of an aim? what are the types of aim?

• what the study is trying to find out

two ‘types’:

• general (e.g. to see if the environment affects obedience methods

• specific (e.g. to see if a rundown building reduces obedience levels in a replica of the Milgram experiment)

what is a hypothesis? (general)

• a prediction about the variables in the study

• it must state an outcome of the research using an IV and DV

what is an alternate/research hypothesis?

• states there will be a difference/change/effect/correlation etc.

• we retain this hypothesis when our results have been found to be significant but we reject it if not

• often uses the predictive tense “will”

• e.g. drug use will cause a higher risk of cancer

what is a null hypothesis?

• states that there is no difference/change/effect/correlation and that any difference occurs by chance and not because of variables manipulated/chosen

• we reject the alternate and retain the null, but if results do support the alternate, we do the opposite

• used to describe results when they do not support the alternate/research hypothesis

what is a directional hypothesis?

• an alternate hypothesis that indicates which direction the results will go in

• look out for words such as higher/lower/greater etc

what is a non directional hypothesis?

an alternate hypothesis that states that there will be a difference, but not how

what is operational definition?

• for variables to be operational, there must be a clear definition of how they will be measured

• e.g. DV = memory → ODV = number of words recalled in one minute

what is an extraneous variable?

a variable that does not vary systematically with the IV

what is a confounding variable?

a variable that changes systematically with the IV so we cannot be sure if any observed change in the DV is due to the CV or the IV

what is reliability?

measure of whether something stays the same, i.e. is consistent

what is validity?

when a test measures what it is intended to measure