experiments Flashcards
what are the purposes of experiments?
they involve the manipulation of an independent variable to see its effect on the dependent variable
what are the three types of experiments?
- laboratory
- field
- quasi
what are laboratory experiments?
an experiment in an controlled environment, all other variables (extraneous variables) are controlled an kept at a constant
what are positives of laboratory experiments?
- high control
- reliable
- replicable
- standardized procedures
- control EV’s
= increases internal validity
what ae negatives of laboratory experiments?
- decreases ecological validity
= artificial environments
= demand characteristics
what are field experiments?
the experiment takes place in a natural environment e.g a participant’s home
what are positives of field experiments?
- increases ecological validity
= natural environments
= low in demand characteristics
what are negatives of field experiments?
- low control
= decreases reliability - EV’s may affect behavior
- lack of consent
what are quasi experiments?
an experiment where the ‘IV’ is naturally occurring and not manipulated by the experimenter e.g hair colour or eye colour
what are some positives of quasi experiments?
- you are able to investigate participants that would otherwise not be able to be investigated as i would be impossible or unethical
what are some negatives of quasi experiments?
- it may be difficult o gather participants sometimes
which is the ‘cause’ IV or DV?
IV
which is the ‘effect’ IV or DV?
DV
what are extraneous variables?
factors that can affect the behavior of participants
e.g light, noise or heat etc.
or emotional state of participants, sex, age etc.
what are cofounding variables?
when extraneous variables ‘align’ themselves with he experimenter’s manipulation of the IV, they become cofounding variables
what is meant by experimental control?
preventing extraneous variables from becoming cofounding variables
what is a hypothesis?
a testable statement based on theory or observation, a prediction of the relationship between 2 variables, a prediction of the ‘cause an effect’
what is an experimental (alternative) hypothesis?
this type of hypothesis tests the cause of independent variable on the effect of dependent variable
what are the two types of experimental/alternative hypothesis?
directional (one-tailed)
non-directional (two-tailed)
what is a directional hypothesis?
this hypothesis predicts the direction in which the results are expected to occur e.g ‘significantly more/less’
what is a non-directional hypothesis?
this hypothesis doesn’t predict the expected direction of e outcome, but will state that there is a difference between the two states, the hypothesis does not specify if the behavior will be better or worse, just different
what is a null hypothesis?
the counterpart to the experimental/alternative hypothesis.
‘no difference’ ‘no change’
if the null hypothesis can be rejected statistically, we can accept the experimental/alternative hypothesis
what is experimental designs?
the researcher must decide whether the same participants will be tested in both conditions, or whether different participants will be tested in different conditions
what does two levels of the IV mean?
two or more conditions in an experiment
