Transcript File

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 significance
Recapping the major features of science
For each of the following, answer the questions
below:
• Replicability
• objectivity
a) Define/describe this feature
b) Why is this feature important?
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.
Recapping the major features of science
Theory 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)
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.
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.
Validating new knowledge and the role
of peer review
Outline of purpose
Strengths
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
Limitations
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
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.
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 U
Which stats test?
A researcher conducted an observation of
gender-specific behaviour displayed by girls and
boys in the playground.
Chi square
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
Stats, probability and significance.
Quiz
1.What are p values?
2.What does a p value of 0.05 mean?
3.Define Type 1 and Type 2 errors
4.What P value is likely to cause a Type 1 error? Why?
5.What P value is likely to cause a Type 2 error? Why?
6.What error has been made in the following
• A medical professional says the patient has cancer when
they are healthy
• A psychologist concludes that the intervention did not have
a significant impact on the youth’s addiction when it did.
Answers
1.The probability accepted that results could have happened by chance
2.There is a less than 0.05 or 5% chance that the results happened by
chance
3.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 lenient
5. Type 2- 0.01 because this is being too stringent
6. Type 1 as null is rejected when it shouldnt be. Type 2 as null is
accepted when it should not be