experimental methods and sampling Flashcards
what’s an aim
- general statement of what researcher wants to investigate
what is an independent variable
changing something to see affect on dv
what is a hypotheses
precise statement which states the relationship between variables being investigated
hypothesis can be either directional or non directional
directional - shows the direction of relationship that will be shown in variables
non directional - doesn’t do that
what is a dependent variable
aspect of study thats measured by researcher, has been caused by a change to the IV
what are the 4 types of experiments
field, lab, quasi, natural
What is an experimental method
manipulation of iv to have an effect on the dv, which is measured and then stated in results
what is an extraneous variable
any variable other than the IV that may have an effect on the DV if not controlled
what is a confounding variable
uncontrolled extraneous variables that negatively affect the results
what is a demand characteristic
any cue the researcher or the situation may give which makes the participant feel like they can guess the aim of the investigation,
may lead to P changing their behaviour positively or negatively
what is randomisation
use of chance in order to control for the effects of bias
what is standardisation
using exactly the same procedures and instruction for all participants in an experiment
lab experiment.
- conducted in highly controlled environment
- allow researcher to manipulate one variable (iv) to see effects on another variable (dv)
strength of lab experiment
- replication
researchers can repeat experiments and check result
weakness of lab experiment
-low ecological validity -
high control. = situation artificial , not like real life
field expiemernt
- occur in real world settings
- iv manipulated + any other variable as possible are controlled
strength of field experiment
- high ecological validity
more natural behaviours = high yk my ting
weakness of field experiment
- ethical considerations
invasion of privacy, likely to have been no informed consent
-loss of control
over extraneous variables, precise replication not possible
natural experiment
- researcher takes advtange of pre existing naturally changing iv
strength of natural experiment
- high external validity
as you are dealing with real life issues - provides opportunities
for research that would’ve been impossible to do due to ethical/practical reasons
weakness of natural experiment
- natural occurring events
may be rare this means experiments not likely to be replicable meaning harder to generalise results
quasi experiment
-iv is based on existing difference between people (e.g age or gender)
- p can’t be randomly assigned
strength of quasi experiment
-controlled conditions
= replicable, and likely to have high internal validity
weakness of quasi experiment
- can’t randomly allocate p
may be confounding variables =. makes it harder to conclude that IV was caused by DV
null hypothesis
says there will be no difference between conditions, and that any difference is due to chance
independent group design
two separate groups experience two separate conditions of an experiment
repeated measures design
all participants experience both conditions of an experiment
matched pairs design
participants are paired together on a variable relevent to the experiment
