Research methods revision - PowerPoint Presentation

Slide1

Research methods revision

The next couple of lessons will be focused on recapping and practicing exam questions on the following parts of the specification:

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

Designing studies

Stats, probability and significanceSlide2

Recapping the major features of science

For each of the following, answer the questions below:

Replicability

objectivity

Define/describe this feature

Why is this feature important?Slide3

Jun12

Explain what is meant by replicability (1). Why is replicability an important feature of science (2)?

(5 marks)

(1)

Replicability

is the ability to check and verify scientific information. Candidates could explain replicability as:• the ability to repeat the method to assess if similar findings are achieved• the ability to achieve similar findings(2) Replicability is an important part of the scientific process. Scientific method involves formulating a hypothesis which is tested with empirical research. Research findings are an important part of this process. If we wish to draw conclusions from research studies, the procedures and findings should be repeatable. Unrepeatable results may imply flaws or lack of control within the method used and are of limited use in theory construction.Slide4

Recapping the major features of science

T

heory construction, hypothesis testing, the use of empirical methods are all parts of the scientific process.

What do we mean by hypothesis testing and use of empirical methods?

How are these and theory construction involved in the scientific process? (hint: think about the scientific process cycle)Slide5

Original June15 paper

What is a theory? [2 marks]

A

theory is a framework / explanation for describing a

phenomenon/

behaviour. It may be based on observations about the world or on empirical data derived from hypothesis testing. This question is challenging for students and the definition may well be embedded within the explanation of the part played by theories in the scientific process. Award one mark for a basic definition (eg ‘a theory is an idea or concept about how something works’). Award one further mark for appropriate elaboration. Slide6

Why is theory construction a major feature of how science works? [4 marks]

Theory

construction is a major element of how science works. Science progresses through a cycle in which ideas (theories) are tested by empirical methods and refined in the light of evidence.

• Theory construction enables predictions to be made which can be translated into hypotheses and tested empirically.

• The data obtained from using empirical methods can be used to support / reject / refine the original theory.

• This knowledge allows theory construction and testing to progress through the scientific cycle of enquiry 4 marks Sound Accurate and detailed coverage of the role played by theories in the scientific process covering some of the above bullet points. 2-3 marks Reasonable Reasonable coverage of the role played by theories in the scientific process covering some of the above bullet points. 1 mark basic Very brief or muddled discussion of the role of theories in science.Slide7

Validating new knowledge and the role of peer review

Outline

of purpose

Strengths

Limitations

In peer review research reports are checked in terms of suitability for publication, appropriateness of the theoretical background, methodology, statistics and conclusions. The work is methodologically sound, valid and does not involve e.g. plagiarism of other people’s research.

The authors are not making unjustified claims about the importance of their findings

It helps to ensures that poor quality work is not published in reputable journalsSlide8

Validating new knowledge and the role of peer review

Outline

of purpose

Strengths

Limitations

In peer review research reports are checked in terms of suitability for publication, appropriateness of the theoretical background, methodology, statistics and conclusions. The work is methodologically sound, valid and does not involve e.g. plagiarism of other people’s research.The authors are not making unjustified claims about the importance of their findings

It helps to ensures that poor quality work is not published in reputable journals

Bias – it has been established that a publication bias occurs towards prestigious researchers and research departments

Bias towards positive findings - negative findings and replications are rarely published, though these can be critical in establishing whether important findings are reliable Slide9

Purpose:

In

peer review research reports are checked in terms of suitability for publication, appropriateness of the theoretical background, methodology, statistics and conclusions.

Strengths:

• The work is methodologically sound, valid and does not involve e.g. plagiarism of other people’s research

• The findings are novel, interesting and relevant, and add to knowledge of a particular research area • The authors are not making unjustified claims about the importance of their findings • Peer review ensures research is reviewed by fellow experts • Peer review maintains the standards of published work and allows University research departments to be rated and funded in terms of their quality; • It helps to ensures that poor quality work is not published in reputable journals Slide10

Weaknesses:

Bias

– it has been established that a publication bias occurs towards prestigious researchers and research departments

Bias

towards positive findings - negative findings and replications are rarely published, though these can be critical in establishing whether important findings are reliable

Bias in favour of ‘established’ research areas – novel or unusual research is hard to publish As reviewers are usually working in the same field as the submitted work and competing for limited research funds, there is a temptation to delay or even prevent the publication of competing research Peer review sometimes fails to prevent scientific fraud Slide11

Designing studies

June 2015

paper:

Read all the scenarios carefully in the research methods section and answer Q28 using your knowledge of designing experiments and the mark scheme.Slide12

Stats, probability and significance.

NO PACKS! Which stats test?

An experimenter carried out a study looking at the effects a restricted diet has on memory. Participants were randomly assigned to either the experimental or control group. A memory test was conducted and the scores out of 20 were recorded.

Mann-Whitney USlide13

Which stats test?

A researcher conducted an observation of gender-specific behaviour displayed by girls and boys in the playground.

Chi squareSlide14

Which stats test?

A study was carried out to test the effects of sleep deprivation on concentration

.

The study took place over 3 weeks, each week the

participants

were asked to come into the lab for one night and were deprived of sleep. Participants slept for 1 hour in the first week of the study, 4 hours in the second week and 7+hours for the final week.The participants were asked to complete a complex ‘ spot the difference’ task at the beginning of the study and after each sleep deprivation session. The scores on the task were recorded out of 25.Wilcoxin T Slide15

What are p values?

What does a p value of 0.05 mean?

Define Type 1 and Type 2 errors

What P value is likely to cause a Type 1 error? Why?

What P value is likely to cause a Type 2 error? Why?

What error has been made in the followingA medical professional says the patient has cancer when they are healthyA psychologist concludes that the intervention did not have a significant impact on the youth’s addiction when it did.

Stats, probability and significance.

QuizSlide16

Answers

The probability accepted that results could have happened by chance

There is a less than 0.05 or 5% chance that the results happened by chance

Type 1- Alternative accepted and null rejected when it should not have been

Type 2- Alternative is rejected and Null is accepted when it should not have been

4. Type 1- 0.10 because this is being too lenient5. Type 2- 0.01 because this is being too stringent6. Type 1 as null is rejected when it shouldnt be. Type 2 as null is accepted when it should not be