Research methods

A variable that is purposely manipulated by the experimenter

A dependent variable is the property that is being measured. It relies on the independent variable

Variables that may cause an unwanted affect on the experiment

A variable that has had a systematic effect on the value of the DV

A hypothesis is a testable prediction  which states how changes in the IV will affect the DV

When the whole population has an equal chance of being chosen as participants

• When the effects of a certain variable can be eliminated as a possible confound in an experiment.
• Done through dividing population into subgroups and then randomly selecting participants

When the participants have the same chance of being in the E-group or the C-group

• Advantages: confounds caused by "participant variables" will be eliminated Also possible to use less participants
• Disadvantages: Participants may perform better "practise" or do worse, "boredom, fatigue"

When the participants are both in the E-group and C-group

• Where the researcher is able to identify a variable that is likely to confound and eliminate this variable. 
• Participants are ranked in accordance and allocated in respective groups

• Advantages: The variable in the which the participants are "matched" will not affect the experiment
• Disadvantage: It is time consuming and expensive. If one of the pair drops out, the other must be eliminated

Allocates participants in c-group or e-group at random

• Advantages: Can be done at once, drop outs are unlikely
• Disadvantages: Requires large number of participants to ensure the it is representative of the population.

• The placebo effect refers to the participants' behaviour being influenced by expectations of how they should behave.
• It can be elminated by using a single blind procedure where the participant is unaware whether they are in the c-group or e-group

• Refers to the outcome of the experiment being unintentionally or intentionally influenced by the experimenter
• Can be eliminated by the double blind procedure where neither the experimenter or participant know which group they are allocated in

Non standardised instructions or procedures. The only difference between the control and experimental group must only be the IV