How science works &

Researchmethods

A2

Timing and attack strategy

2 hours in total

Section A and B worth 48 marks

Section C worth 35 marks

70 mins

50 mins

Every mark counts.

6 marks is the difference between a

grade.

The research methods specification

The application of scientific method in psychology

• The major features of science, including replicability, objectivity, theory construction, hypothesis testing, the use of empirical methods.

• Validating new knowledge and the role of peer review.

RMab

5

A good scientist is a skeptic.

Science ≠ laboratory.

Science is important.

Knowledge vs belief.

The scientific processObserve behaviour around you

Develop an explanation/hypothesis

Produce a research prediction

Conduct a study to test the prediction and get results

Draw conclusions

Refine the explanation/hypothesis

Bibb Latané and John DarleyBibb Latané and John Darley

Exam FOCUS

A drug company sells special capsules claiming they will improve exam performance. Their claims are based on observations made by their own research unit involving a local school.

Explain why their claim cannot be accepted as scientific evidence. Refer to some of the major features of science in your answer. (6 marks)

RMab

Validating new knowledge1. The scientific process

2. Peer review

Scientists find out about each other’s work by reading journal articles.

AbstractIntroduction

MethodResults

DiscussionConclusion

• Tends to reject papers that challenge conventional research.

• Tends to reject replications.• Tends to favour well-known

researchers.• Is anonymity better? Or worse?• Errors don’t get corrected.• Web publications.

Exam FOCUSJune 2012

Design a study to test whether there is a difference in the musical ability of left-handed students and right-handed students. You have access to a sixth form of 200 students. You should: • identify the design that you would use • explain an appropriate sampling method and justify your choice • describe the procedure that you would use, including details of how

you would assess musical ability • write a suitable debrief for these participants. (10 marks)

Exam FOCUSDesign (1 mark)

Independent groups or matched pairs

Sampling(2 marks)

Award 1 mark for explaining an appropriate sampling method and 1 further mark for justifying why this method would be appropriate.

Stratified sampling  would be used as there can be two stratas, left and right-handed. Once the students are put into these groups, random sampling can be used to reduce any bias. This can be done by placing the name of every student who is left-handed on a piece of paper and then being folded and put in a sealed box. Then there should be 40 students chosen out of the box. The same procedure should be repeated for right-handed students. There will then be two groups of 40 students, left and right handed. 

Exam FOCUSProcedure and assessment of musical ability(4 marks)

Award 1 mark for procedure, 1 mark for assessing musical ability and two further marks for elaboration of either or both of these.

The procedure  would involve each participant (P) going into a room alone, with only a piano and sheet showing how to play a certain song. Each P will have 10 minutes to learn as much as possible. They will then play the song to a qualified music teacher who can rate their performance in terms of musical grades. By having got a piano and now a piece of music it limits the number of Ps who have high musical ability on one instrument although there will be anomalies for those who already have high musical ability on the piano. Also by having a qualified music teacher use official grades, this gets rid of the validity issues the teacher previously had.

Exam FOCUS

Debrief(3 marks)

Award up to 3 marks for writing a debrief. This could include the aim of the study, thanking participants for taking part, asking if they have any questions, relevant ethical considerations. If this is not suitable to be read out to participants, maximum 1 mark.

Ps will be debriefed  after performing. The debrief would be: Thank you for participating in our study. We can ensure that your identity will be kept completely anonymous along with the records of your musical ability. If you have any further questions or concerns, do not hesitate to ask . debrief. rk scheme).

The research methods specificationDesigning psychological investigations

• Selection and application of appropriate research methods.

• Implications of sampling strategies, for example, bias and generalising.

• Issues of reliability, including types of reliability, assessment of reliability, improving reliability.

• Assessing and improving validity, including internal and external.

• Ethical considerations in design and conduct of psychological research.

RMab

Exam FOCUSWriting hypotheses

Blanco et al. conducted a study to test the effectiveness of using SSRIs to treat gamblers. Research had shown that low levels of the neurotransmitter serotonin may be a cause of addictive behaviour. SSRIs raise the levels of serotonin.

32 gamblers were recruited for this study. Over a period of six months one group were given SSRIs (200 mg/day) and the other group took a placebo. At the end of the trial period the researchers assessed gambling behaviour in terms of reduction in money and time spent gambling per week.

Write a directional hypothesis for this study. (3 marks)

Exam FOCUSWriting too much or too little

A psychologist developed a scale to measure personality. It was important for this scale to be reliable. To test this he gave the scale to 30 participants.

What is meant by reliability? (1 mark)

Explain how the reliability of the scores in this study could be checked. (4 marks)

Exam FOCUSWriting too much or too little

Observation of one child – number of verbally aggressive acts

Explain why the psychologist is concerned about inter-rater reliability? (4 mark)

Many candidates produced lengthy answers, wasting time explaining inter-rater reliability or reliability.

If the psychologist does find low reliability, what could she do to improve inter-rater reliability before proceeding with the observational research? (4 marks)

Most candidates could offer at least one solution to this issue but many stopped after making their initial point e.g. 'give them more training’.

Time slots 0-10 11-20

21-30

31-40

41-50

51-60

Observer A 2 5 0 6 4 3

Observer B 4 3 2 1 6 5

Exam FOCUSApplying your knowledge

The psychologist needed to obtain informed consent from her participants. Write a brief consent form which would be suitable for this study. You should include some details of what participants could expect to happen in the study and how they would be protected. (5 marks)

The A2 Examination: January 2010 exam Unit 4

Topic: Research methodsA psychologist was interested in testing a new treatment for people with eating disorders. She put adverts in several London clinics to recruit participants. Thirty people cam forward and they were all given a structured interview by a trained therapist. The therapist then calculated a numerical score for each participant as a measure of their current functioning, where 50 indicates excellent, healthy functioning and zero indicates failure to function adequately. The psychologist then randomly allocated half the participants to a treatment group and half to a no-treatment group. After eight weeks, each participant was re-assessed using a structured interview conducted by the same trained therapist, and given a new numerical score. The therapist did not know which participants had been in either group.For each participant, the psychologist calculated an improvement score by subtracting the score at the start of the study from the score after eight weeks. The greater the number, the better the improvement.

Table 1: Median and range of improvement scores for the treatment and no-treatment group Treatment group No-treatment group Median 10.9 2.7 Range 2.1 0.8

Exam FOCUSJan 2010 Part (f)

Must mention not getting treatment.For full marks must include both procedural and ethical points.

Sound = 5 marksReasonable = 4 – 3 marks

Basic = 2 marksRudimentary = 1 mark

If you take part in this study you are agreeing to be interviewed by a psychologist about your eating habits and other aspects of your life. Your current health will be assessed twice by the psychologist in two separate interviews. You will be part of a group that either receives treatment or doesn’t receive treatment. All information you provide will be kept confidential.

3 marks

The research methods specification

Candidates will be expected to:

Design investigations.

Understand how to analyse and interpret data arising from such investigations.

Report on practical investigations.

In order to gain sufficient understanding … candidates will need to practise these skills by carrying out, analysing and reporting small-scale investigations.

RMab

Design it yourself Exam FOCUS

Test a new idea:

People notice the change when the person is the same age as them rather than a different age.

You have access to a sixth form of 200 students.• identify the design that you would use • explain an appropriate sampling

method and justify your choice • describe the procedure that you would

use, including details of how you would assess the DV

• write a suitable debrief for these participants.

What other questions?

The research methods specificationData analysis and reporting on investigations

• Appropriate selection of graphical representations.

• Probability and significance, including the interpretation of significance and Type 1/Type 2 errors.

• Factors affecting choice of statistical test, including levels of measurement.

• The use of inferential analysis, including Spearman’s Rho, Mann-Whitney, Wilcoxon, Chi-Squared.

• Analysis and interpretation of qualitative data.• Conventions of reporting on psychological

investigations.

RMab

Probability and significance

Null hypothesis

There is nothing going on.

Alternative hypothesis

This is the fixed pack.

There is something going on.

Probability and significance

1 card

Probability is 50:50 that the card is redi.e. 0.5

50 %

2 cards

0.5 x 0.5 = 0.25

25 %

3 cards

0.5 x 0.5 x 0.5 = 0.125 About 12 %

4 cards

0.5 x 0.5 x 0.5 x 0.5 = 0.0625 About 6 %

5 cards

0.5 x 0.5 x 0.5 x 0.5 x 0.5 = 0.03125

About 3 %

6 cards

0.5 x 0.5 x 0.5 x 0.5 x 0.5 x 0.5 = 0.015625

About 1 %

5 % level

Probability and significance

I keep seeing my best friend’s

boyfriend around campus talking to this

other girl

He says nothing is going on

If nothing is going on, how come he

seems to always be with her?

What’s the likelihood of that

if there is nothing going

on?

REJECT NULL HYPOTHESISREJECT NULL HYPOTHESIS

ACCEPT ALTERNATIVEACCEPT ALTERNATIVE

THERE IS SOMETHING GOING ON

THERE IS SOMETHING GOING ON

Probability and significanceResearch study

➨ Group A does test with loud music➨ Group B does test in silence

Null hypothesis?

Alternative hypothesis?

We do the study …

RMab

There is nothing going on.

There is no difference between test results from

Group A and B.

There is something going on.

Test results from Group A and B are different.

Probability and significanceWhat can you infer from these graphs?➨ There is something going on➨ There is nothing going on➨ Not sure

RMab

RMab

Inferential statistics

RMab

Levels of measurementNominal namesOrdinal orderedInterval equal intervals

Bandura’s Bobo study involved two groups of children, one group saw a violent model and the other group saw a non-violent model. Both groups were later rated for their aggressiveness in a play situation.

In a similar study, children were not rated but were simply classed as aggressive or not.

Inferential statistics RMab

Determining significance

The observed (calculated) value of rho is 0.456 ….

The hypothesis was directional.

There were 15 participants.

5% level of significance.

Is it significant?

Table of critical values for Spearman’s rho

Observed value of rho must be equal or greater than the critical value in the table for significance to be shown)

RM

Level of significance for a one-tailed test

0.05 0.01

Level of significance for a two-tailed test

0.10 0.02

N = 15 0.443 0.521

16 0.429 0.503

17 0.414 0.485

Stating conclusions

The observed (calculated) value of rho is 0.456 ….

The critical value (p ≤ 0.05) is 0.443.

It is significant.

RM

Statement of results

As the observed value (0.456)

is greater than the critical value (0.443)

at p ≤ 0.05,

this means we can reject the null hypothesis

and conclude that …. [state the hypothesis].

Type 1 and Type 2 errors

If you were on a jury which mistake would you avoid?

Convicting an innocent man (Type 1 error).

Letting a guilty man go free? (Type 2 error)

Null hypothesis: This man is not guilty i.e. innocent.

Truth

Guilty Not guilty

Test result

Guilty verdict True positive

False positive(guilt reported)TYPE 1 ERROR

Not guilty verdict

False negative (guilt not detected)

TYPE 2 ERRORTrue negative

Which way would you lean?

Null hypothesis: This person is not ill i.e. is healthy. There is nothing going on.

Truth

Has cancer No cancer i.e. healthy

Doctor says you have cancer

True positiveFalse positive

(illness reported)TYPE 1 ERROR

Doctor says you are healthy

False negative (illness not detected)

TYPE 2 ERRORTrue negative

Truth

H1 is correctThere is

something going on.

Ho is correctThere is nothing

going on.There is no real

effect.

Test result

Reject null

True positive False positive(likely when p too lenient i.e.

10%)TYPE I ERROR

Accept null

False negative (likely when p too stringent

i.e. 1%)TYPE II ERROR

True negative

Type 1 and 2 errors happen when a hypothesis is mistakenly rejected.

Type I error H0 is rejected when it is in fact true.

Type 2 error H0 accepted when it is false.

Type 1 error happens when we set the bar

too high.

Exam FOCUSJan 2010 Part (c)

A psychologist found a significant difference at the 5% level for a one-tailed test (p ≤ 0.05).

What is the likelihood of the psychologist having made a Type 1 error in this study? Explain your answer. (2 marks)

No credit for explaining Type 1.

1 in 20 chance (5%) or less that the results are due to chance and that we have rejected null hypothesis that is true (false positive)

The likelihood of a Type 1 error is about average as the level of significance chosen (5%) is neither too high or too low).

Qualitative research Source

Newspapers, TV, interviews etc

Thematic analysis Top down Bottom up Behavioural

categories/themes emerge

Summarising Quotes Examples

One significant indication of schizophrenia was my inability to plan my future. I took courses in University that sounded interesting with no real plan. I was notably incapable of developing another long term romantic relationships and in fact was very anxious in any kind of social situation.At graduate school I kept going to the university clinic about my physical health, afraid that my health was going to fall apart. I thought the town water supply had become contaminated because it tasted metallic to me. I was convinced I was going to die of a heart attack. The most frightening was that I had contracted a form of syphilis that couldn't be detected by regular lab tests.

RMo

Study past questions and mark schemes.

Study the report on the exam to see where students went wrong.

Write enough for the marks available.

But don’t write too much.

Answer the question.