control of variables Flashcards
define extraneous variables
any variable other than the IV that may have an effect on the DV (if it isn’t controlled)
e.g age of participants
what are the 2 types of extraneous variables
participant variables
situational variables
define participant variables
individual difference between participants that may affect the DV
define situational variables
features of the experimental situation that may affect the DV
define confounding variables
systemically change with the IV (any other variable than the IV that may have affected the DV so we cannot be sure of the true reason for the DV changing)
what is the “please you” effect
over perform to please the experimenter
what is the “screw you” effect
under perform to sabotage the results
define investigator effects
any effects of the researchers behaviour that could change the outcome of the results
how do you control extraneous variables
standardisation - all participants are subject to the same experimental condition (environment, time)
how do you control confounding variables
randomisation - using chance in order to control effect of bias in an experiment
(randomly allocating questions to participants)