Completing your experiment

What is the aim of your experiment?• What is your operational hypothesis?

What are you measuring?• An independent variable (IV) is deliberately manipulated or varied in

some way by the experimenter. This is planned before the experiment begins.

• The dependent variable (DV) is the property that is measured in the research. Its value depends on the IV and that is why it is called ‘dependent’.

• Try and get rid of these prior to study• An extraneous variable is a variable other than (‘extraneous to’) the

IV that could cause changes in th value of the DV. Extraneous variables are undesirable.

• A confounding variable is a variable other than the IV that has a systematic effect on the value of the DV. If a confounding variable exists, the research is usually a waste of time and no valid conclusions can be drawn, so very stringent procedures are used to prevent this happening.

Forming a hypothesis

• A hypothesis in psychological research is a clear statement predicting how changes in the independent variable(s) will affect the value of the dependent variable(s). A hypothesis should also clearly state the population about which the researcher intends to draw conclusions. WHAT ARE THE IV AND DV?

• > That for students showing examination anxiety in VCE Psychology, rest periods taken during examinations will lead to decreased state anxiety.

That Unit 3 and 4 psychology students who have regular study schedules throughout the academic year will achieve better study scores than those who cram in the last two weeks before the exams.

• Operational definitionsOperationalisation of a variable means that it is stated in• terms that show how it is measured. For example:• > age—operationalised as age in total months• > IQ—operationalised as the score on a 40-item multiple choice• test

Who is your population?• What sampling are you using?• A) random sampling (everyone in the population has the same

chance)• B) Stratified sampling/ Random-stratified samplingare processes by which the effects of a certain variable can be eliminated as a possible confound in an experiment. This involves a number of procedures:• 1 Identifying a property that we believe may interfere with the

effects of the IV on the value of the DV.• 2 Measuring that property for each member of the population.• 3 Dividing the population into particular strata (groups) based

on the value of that variable.• D) Convenience sampling – whoever is available at the time

Control and Experimental group• The basic experimental method uses two different groups

called the experimental group (E-group) and the control group (C-group).

• Members of the experimental group are exposed to the IV. This is referred to as the condition that receives the treatment. The treatment is the variable that the experimental group participants receive and members of the control group do not.

Splitting up your groups• Random allocation means that all participants who have been

selected for an experiment must have an equal chance of being in E-group or C-group.

• When the sample is large enough, this means that the E-group and C-group will be equivalent on all participant characteristics and the presence or absence of the IV will be the only difference between them—meaning that it is entirely responsible for any difference in the measured DV.

What is your experimental design?• A) In repeated measures design (also known as within

participants design), each participant is part of both E-group and C-group. The procedure can also suffer from confounding variables known as order effects: a Participants may perform better on the task when doing it a second time because of the effect of practice. A better method of overcoming order effects is counterbalancing. In the counterbalancing procedure, half the participants will first perform the task with the IV present (experimental condition) and then perform the task with the IV absent (control condition).

• B) The matched participants design enables a researcher to identify a variable that is likely to confound and to eliminate the effects of this variable from the experiment.

C) The independent groups design (also known as between participants design) allocates participants to E-group or C-group at random.

The Placebo and Experimenter Effect• The placebo effect refers to the participants’ behaviour being

influenced by their expectations of how they should behave, caused by the belief that they have received some treatment.

• The placebo effect can be eliminated by using a single-blind procedure in the experimental process—allocating participants to groups in such a way that they do not know whether they are in E-group or C-group.

Experimenter Effects• The experimenter effect refers to the outcome of an

experiment being unintentionally (or even intentionally) infl uenced by the experimenter. It occurs, for example, if the experimenter treats the members of E-group and C-group differently and therefore infl uences the behaviour of participants and the outcome of the experiment. The experimenter effect can be addressed by using a double-blind procedure in the experimental procedures, ensuring that neither the experimenter nor the participants are aware of which participants are in E-group or C-group.

What Data are you collecting?• > Qualitative data refer to descriptions of the characteristics

of what is being• studied. In psychological research this could be:• > emotional state: happy/sad/angry, etc.• > difficulty of task: easy/moderate/difficult/very difficult.• > Quantitative data refer to measurements—numerical

information about the variables being studied. Most psychological research aims to gather quantitative data because we can perform statistical procedures on these and, provided the data are accurate and precise, we can determine whether our results are significant and our hypotheses can be supported. Data can also be subjective or objective.

P Values - Is your test statistically significant?• To do this, the researcher calculates the mean score for the E-

group and the C-group and uses inferential statistics to decide whether the difference is statistically significant or is likely to have been caused by pure chance.

• The inferential tests will give a probability that the difference is caused by chance. This is expressed as a p-value where p =0.03 means that there are three chances in 100 (3%) that this difference would be achieved by chance alone.

• Psychologists are generally prepared to accept that a difference is statistically significant if the difference could have been caused by chance alone on five or less times in 100. This is stated as p 0.05.

Conclusions and Generalisations• A conclusion is the final decision about what the results mean.

This conclusion must be stated in terms of the original hypothesis. So a conclusion would be that the hypothesis is rejected or supported.

• A generalisation is a judgment about the extent to which the research findings can be applied to the population represented by the sample. The ability to generalise from a sample relies on all the following conditions being met:

> The sample must represent the population of interest.> The results must reach statistical signifi cance.> The effects of all potentially confounding variables must have been controlled.

Remember your Ethics• Confidentiality (privacy)• Voluntary participation• Withdrawal rights• Informed consent: Participants must be given information

about a study before they agree to take part. For participants who are either too young or too intellectually disabled to give their consent, their guardian must be given the information before giving consent on their behalf.

• Deception in research: This is only permitted if the results would be confounded if the participants had much information before taking part in the study.

Writing an ERA

ERA Structure

References

Discussion

Results

Method: Participants, Materials & Procedure

Introduction

Abstract

Title Page

Title• Appears on the cover sheet.• Should contain fewer than 12

words.• Must incorporate IV & DV• Avoid unnecessary terms such as, “a

study of..”• For example: The Effect of Exposure to TV Violence on Aggression and Hostility

IV – the variable which the researcher changes in order to assess it’s effects on the participants’ responses.

DV – the participants’ responses that are affected by the IV.

TV VIOLENCE & AGGRESSION 1

Title: The Effect of Exposure to TV Violence on Aggression and

Hostility Subject: Psychology Assignment: Laboratory Report 1 Student No: 123456 Teacher: Miss Koomen Date Due: 12th September, 2012 Submitted: 12th September, 2012 Extension: Word Count: 2,012

VariablesAn independent variable (IV) is deliberately manipulated or varied in some way by the experimenter.

The dependent variable (DV) is the property that is measured in the research. Its value depends on the IV and that is why it is called ‘dependent’.

An extraneous variable is a variable other than(‘extraneous to’) the IV that could cause changes in the value of the DV.

A confounding variable is a variable other than the IV that has a systematic effect on the value of the DV.

Abstract• The abstract should be on the

second page, after the cover sheet/title.

• WRITE THE ABSTRACT LAST• It is a brief summary of the

whole investigation, usually presented in one paragraph.

• It should:• State the aim (purpose) of the

experiment;• Outline the main features of

the method (participants & procedure used); and

• Summarise the results and the conclusions.

TV VIOLENCE & AGGRESSION 2

Abstract

The prevalence of violence on TV, even in children’s programs, has continued to soar over the last decade. To investigate whether exposure to violence on TV promotes mistrust of strangers, 48 psychology students rated the extent to which a stranger in a photograph seems untrustworthy and hostile. Before they rated this person, half the participants watched a violent TV program; the remaining participants watched a quiz show. As hypothesised, participants who watched the violent program were more likely to perceive the stranger as untrustworthy and hostile than were participants who watched the quiz show. These findings suggest the violence that is depicted ubiquitously in the media could promote distrust, which ultimately provokes aggression.

AimParticipants

Procedure

Results

Conclusions

Introduction• The introduction should begin on the third page.• You need to state the title again.• The purpose of the introduction is to explain why the study was

conducted.• First paragraph should highlight the importance of your study in

regards to human behaviour.• You then need to review previous research. You only need to use

the three readings given to you.• Refer to background information relevant to your study. • When doing this you should summarise the relevant theory and the

results of past research.

Introduction

• The last paragraph of the introduction should:• state the aim of

your study; and• present your

hypothesis.• Relate your hypothesis

directly to theory.

Example of an Aim and Presentation of Hypothesis

The aim of this study was to investigate whether exposure to violence on TV promotes mistrust of strangers. As predicted by the agitation model, it is hypothesised that exposure to violence on TV should promote mistrust towards strangers.

Method• Follows immediately after the Introduction on the

same page with a separate heading.• It is broken up into three subheadings:• Participants – number (males and females if recorded),

age, population from which the sample was drawn.

• Materials - A list of equipment & materials used.

• Procedure – A chronological account of every important event that participants experienced during the study. Describe the steps involved in conducting the investigation. Full sentences, not dot points.

Results• Immediately follows the Method section on the same page

and uses a new subheading.• Present the results, but leave the discussion (i.e. Present the

raw data, don’t discuss what the data means).• You will be provided with two tables for which you have to

draw a graph for each.

Results – Drawing Graphs

It is hypothesised that exposure to violence on TV should promote mistrust towards strangers.

Discussion

• Follows immediately after the Results on the same page and uses a new subheading.

• Start by reiterating the aim and making a statement that either accepts or rejects the investigation’s hypothesis based on the results obtained.

Discussion (first paragraph example)

This study examined whether exposure to violence on TV promotes mistrust of strangers. The results supported the hypothesis that exposure to violence promotes the perceived hostility, but not perceived incompetence, of strangers.

….

Discussion• Next, describe the results obtained from the investigation and

give a valid explanation.• Describe the general relevance of the results to the population

from which they were drawn. Do the results of the investigation support or contradict previous research identified in the introduction?

• Discuss any limitations of the study. There will be heaps!!• Possible confounding variables??• Think about other things that may have influenced whether or

not people helped other than the independent variable.• What recommendations would you make for further research

in light of these limitations? What might you change if you were to do the study again?

Discussion• Describe any ethical

considerations relevant to the research.

• The final paragraph of your Discussion should provide a clear conclusion.

• This can include:• The main findings in one or two

sentences.• The theories these findings

support in one or two sentences.• Some of the complications or

limitations of the study• Whether the results be

generalised to a wider population.

Example Conclusion

In conclusion, this study revealed that exposure to violent TV programs promoted mistrust of strangers presented in photographs. These findings support the theory that individuals feel agitated and anxious after they watch violent acts, and these emotions provoke suspicion. Nevertheless, future research is needed to determine whether or not these effects persist over many hours, days, and months. The results of this investigation show that…

Some concepts to think about when writing your report:• Short term memory• Long term memory• Sensory memory• Maintenance and elaborative rehearsal• Serial Position Effect