research methods (variables & hypothesis)

Experimental Research: Where cause meets effect

Lesson 12:Research Methods

(Variables and Hypothesising)

Saturday, 28 January 2012

Lesson 11 Brain Research Method Exam Question

a) What information about the brain does positron emission tomography (PET) provide? (1 mark)

b) When compared to computerised tomography (CT), outline one advantage of using positron emission tomography (PET). (1 mark)

c) What is the difference in the information provided by magnetic resonance imaging (MRI) and functional magnetic resonance imaging (fMRI)? (1 mark)


Model Response:

a. What information about the brain does positron emission tomography (PET) provide? (1 mark)

Either of:

• the PET scan shows which areas of the brain are active while certain tasks are performed

• the PET scan gives information about brain functioning.

b. When compared to computerised tomography (CT), outline one advantage of using positron emission tomography (PET). (1 mark)

Advantages of PET include:

• CT is static while PET shows the brain in action

• CT shows structural features and location of damage while PET shows functional areas

• PET is more sensitive than CT in detecting areas of brain damage

• unlike CT scans, PET scans are colour-coded, which aids interpretation

c. What is the difference in the information provided by magnetic resonance imaging (MRI) and functional magnetic resonance imaging (fMRI)? (1 mark)

Differences include:

• fMRI uses a magnetic field to create a three dimensional image of the brain where any two dimensional slice can be selected, and also displays brain activity on the screen

• MRI shows only the structure of the brain.


Objectives: Lesson 12

• Outline the scientific method in psychological research

• Identify variables including the dependent, independent, extraneous and confounding variables

• Construct a research and operational hypothesis of a research question


Characteristics of an experiment

• IV is the variable selected and tested by the researcher to assess effects on the DV (i.e participants responses)

• It is assumed that changes in the DV will result after exposure to the IV.

• IV and potential unwanted variables (e.g extranious variables) are controlled

• Use of random allocation of participants to different conditions (groups) ensures uniform distributed participant characteristics that can affect the DV.


Variables Independent variable – the variable that is changed by the

experimenter, interested in its effect. We want to see the effect of the IV on the DV

Dependent Variable – measures the effect of the IV, see if the IV has effected the DV


Activity:

Research Question: Does drinking alcohol effect driving?

Identify the IV and DV Write a research hypothesis


Experimental group and Control group

Experimental group: Participants exposed to the treatment condition, i.e the IV manipulation.

Control group: Participants not exposed to the IV manipulation.


The Research Hypothesis

Hypothesis – a testable prediction relating to the outcome of the research being conducted, a prediction that one variable (IV) will effect another variable (DV) in a certain way.


Example Research Question: Does smoking marijuana effect driving

performance?

It was hypothesised that participants who smoke marijuana will perform worse on a driving test as compared to participants who have not smoked marijuana

Independent Variable -

Dependent Variable -

smoking marijuana

driving performance


Variables that need to be operationalised Smoking MarijuanaDriving PerformanceThe population – who we are testing

The Operational Hypothesis

Smoking Marijuana – smoking one joint containing 500 milligrams of pure marijuana (not mixed with tobacco) 20 minutes before taking a driving test

Operational Definitions

Driving Performance -% score on VIC Roads, “Are you Road Ready?”driving simulator

Population - Victorian drivers aged 18 – 25


The Operational Hypothesis

It was hypothesised that Victorian drivers aged 18 – 25 who have smoked marijuana (smoking one joint containing 500 milligrams of pure marijuana 20 minutes before taking a driving test) will perform worse on a driving test (obtain a lower % score on the VIC Roads “Are you Road Ready?” driving simulator) compared to participants who have not smoked marijuana.


Activity:

Write a operational hypothesis for your research question.


Extraneous and Confounding Variables

Confounding variable: Any variable, other than the IV, that is uncontrolled and allowed to change together with the IV, thereby having an unwanted effect on the DV

Extraneous Variable: Any variable, other than the IV, that can cause a change in the DV and therefore affect the results of an experiment in an unwanted way. An extraneous variable may become a confounding variable.


Watch Clip Below Summary


Activity:

1)Identify one extraneous variable.2)Identify an ethical breach in the

experiment.


Revision

Do drivers who have more experience behind the wheel have less

accidents than less experienced drivers?

IV =

DV =

EV =

Research Hypothesis:

Operational Hypothesis:


research methods (variables & hypothesis)

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