SCIENCE INQUIRY YEAR 11/12

select the sampling techniques

• . random allocation

• . convenience

• . snowballing

• . stratified

qualitative subjective

• likert scale

• Galvanic Skin Response (GSR)

• checklist (fixed response)

• heart rate

qualitative objective

• Heart rate

• Likert scale

• interview

• breathing rate

convenience sampling

• collecting a sample through word of mouth

• using a chance process to collect a sample

• collecting a sample that is readily available to the researcher

• technique ensures the sample contains the same proportions of participants from each social group

types of reliability

• test-retest

• internal consistency

• predicitive

• face

what is the difference between population and a sample

what is the difference between random sampling and random allocation

list two sources of extraneous and confounding variables

Answer explanation

. experimenter effects

. demand characteristics

list 3 ways to minimise the effects of extraneous and confounding variables

Answer explanation

1.Random allocation of participants - spreads out differences between participants and hopefully reduces participant differences

2.Single-blind procedures - when the participants do not know whether they have been assigned to the control or experimental group (but the experimenter does). The control group is given a placebo (a substance that looks like the real thing but does not have the active ingredient (e.g. decaf coffee). This reduces the impact of demand characteristics on the results.

3.Standardisation of procedures and instructions – make sure the test is delivered in the same way to all participants and all test conditions are the same. Reduces extraneous variables due to the environment.

list 4 types of validity

Answer explanation

1. 1. face validity

2. 2. construct validity

3. 3. concurrent validity

4. 4. predictive validity