Variables

Question 1

Correlational method

Answer 1

Sometimes researchers simply want to establish the association between 2 variables, they would use a correlational method (height - weight)

Question 2

Experimental method

Answer 2

Sometimes researchers want to establish the ‘cause and effect’ relationship between 2 variables; how one variable affects the other. In this case, they would use the experimental method (caffeine intake - lack of sleep).

Question 3

The correlational method does not require you to identify different types of variables whereas the experimental method does:

Answer 3

1. Independent variable (IV)
2. Dependent variable (DV)
3. Extraneous variable (EV)
4. Confounding variable (CV)

Question 4

Independent variable

Answer 4

In the experimental method, we are interested in the effect of one variable on another variable. The experimenter manipulates the independent variable. The different levels of IV are the experimental conditions.

Question 5

Dependent variable

Answer 5

The dependent variable is that which measured (effect). The values of the dependent variable depend on the independent variable (cause). In an ideal experiment, all variables except the independent variable remain constant.

Question 6

Extraneous variable

Answer 6

There may be other factors that affect the dependent variable, these are called extraneous variables. Types of extraneous variables:
1. Participant variables - age, IQ, motivation
2. Situational variables - testing conditions, instructions given
3. Investigator variables - age, gender, ethnicity

Question 7

Confounding variable

Answer 7

Sometimes extraneous variables cannot be kept constant and change across conditions, then they become confounding variables. Experimental method is aimed at preventing extraneous variables becoming confounding.

Question 8

Controlling extraneous variables

Answer 8

1. Participant variables - are controlled by experimental design (random allocation to different conditions).
2. Situational variables - are controlled by standardisation (keeping all variables constant), if repeated measures (order effect) then counterbalancing (half of participants in one condition first and then the other and vice-versa).
3. Investigator variables - random allocation of researcher if more than one.

Question 9

Other situational variables

Answer 9

• Demand characteristics - are cues in the environment that help the participant work out the hypothesis and behave in a way as to support it. Controlled by single blind technique (where the participant don’t know the hypothesis).

Question 10

Other investigator variables

Answer 10

Investigator effects - are the influence of the researcher whereby their expectations could lead to a ‘self-fulfilling prophecy’. Controlled by double blind technique (where neither the participants nor the research assistant know the hypothesis)

Question 11

Operationalising variables

Answer 11

Means operating. In the case of the dependent variable, operating refers to how you will measure the dependent variable. In the case of independent variable, operating refers to how you will manipulate the independent variables.