STAT251 Design of Research Studies
What proportion of New Zealanders favour legalisation of cannabis? How many manatees inhabit the waters of Florida? Is aspirin a useful way of reducing the risk of a heart attack? These questions are typical of those posed by scientists working in the natural and life sciences. In this course, we focus on how research can best be carried out in order to help answer such questions. We consider some straightforward concepts as well as formulae that can help us decide how large our research study needs to be.
PLEASE NOTE: The contents of this page are meant only as a guideline of what to expect during the paper. The lecturers reserve the right to adjust some details of the paper during the year, as is deemed appropriate.
In this course we aim to give students an understanding of the ideas and methods that are useful in designing a research study in the natural, life and social sciences. This is achieved by relating the appropriate methods of analysis to real-life research situations, and by considering some of the most common mistakes that occur when designing a research study. The emphasis is on understanding the motivation, principles and methods rather than the mathematics underlying them. The course is designed for both general science students and those wanting to specialize in statistics.
Some of the topics covered include random and systematic sampling, cluster sampling, stratified sampling, basic experimental designs, replication, power analysis, experimental units, blocking, factorial designs, nested designs and repeated measurement designs.
Any student who has taken either of the 100-level statistics papers can take this paper. It is suitable for any student majoring in sciences as a key to carrying out a scientific research project. This paper will help students to understand the basic principles of sampling, as well as the design of experiments and surveys.
STAT110 or STAT115 or BSNS102 or BSNS112
The course is divided into four sections of material. These sections may include the following topics:
Study Design Theory
- types of studies: observational, quasi-experimental, experimental
- hypotheses and theories
- relationship between objectives and design
- correlation and causation
- constraints on study design
- bias and variance
- experimental units
- sample size
- error rates
- data types: continuous, discrete, binomial, categorical
- effect size estimation
- sources of heterogeneity and variance
- sampling frame and population of inference
- simple random sampling
- stratified random sampling
- systematic sampling
- cluster sampling
- model building
- pre-experimental data simulation and analysis
- covariates and confounding variables
- controlled experiments
- classical designs
Reference (copies on hold in Science Library)
The design and analysis of research studies, Bryan Manly (Q180.55 S7 M858)
Introductory Statistics with R, Peter Dalgaard (QA276.4.D3584)
Austina S S Clark, room 117
5 lectures per fortnight; Monday, Wednesday and alternate Friday at 11am in room 241.
1 hour per week, either Friday at 12pm or Tuesday at 3pm in lab B21.
12 hours per week
The internal assessment is made up of 6 bi-weekly assignments worth 15% of the final mark, which will consist of questions related to lecture and lab material, and a 1-hour mid-semester test worth 25% of the final mark.
Late assignments are subject to a 10% penalty per day, unless prior permission has been received by the lecturer.
Final Exam format
3 hours long, with 6 questions of equal value, all of which are to be answered.
Your final mark F in the paper will be calculated according to this formula:
F = 0.6E + 0.15A + 0.25T
- E is the Exam mark
- A is the Assignments mark
- T is the Tests mark
and all quantities are expressed as percentages.
Students must abide by the University’s Academic Integrity Policy
Academic integrity means being honest in your studying and assessments. It is the basis for ethical decision-making and behaviour in an academic context. Academic integrity is informed by the values of honesty, trust, responsibility, fairness, respect and courage.
Academic misconduct is seeking to gain for yourself, or assisting another person to gain, an academic advantage by deception or other unfair means. The most common form of academic misconduct is plagiarism.
Academic misconduct in relation to work submitted for assessment (including all course work, tests and examinations) is taken very seriously at the University of Otago.
All students have a responsibility to understand the requirements that apply to particular assessments and also to be aware of acceptable academic practice regarding the use of material prepared by others. Therefore it is important to be familiar with the rules surrounding academic misconduct at the University of Otago; they may be different from the rules in your previous place of study.
Any student involved in academic misconduct, whether intentional or arising through failure to take reasonable care, will be subject to the University’s Student Academic Misconduct Procedures which contain a range of penalties.
If you are ever in doubt concerning what may be acceptable academic practice in relation to assessment, you should clarify the situation with your lecturer before submitting the work or taking the test or examination involved.
Types of academic misconduct are as follows:
The University makes a distinction between unintentional plagiarism (Level One) and intentional plagiarism (Level Two).
- Although not intended, unintentional plagiarism is covered by the Student Academic Misconduct Procedures. It is usually due to lack of care, naivety, and/or to a lack to understanding of acceptable academic behaviour. This kind of plagiarism can be easily avoided.
- Intentional plagiarism is gaining academic advantage by copying or paraphrasing someone elses work and presenting it as your own, or helping someone else copy your work and present it as their own. It also includes self-plagiarism which is when you use your own work in a different paper or programme without indicating the source. Intentional plagiarism is treated very seriously by the University.
Unauthorised Collaboration occurs when you work with, or share work with, others on an assessment which is designed as a task for individuals and in which individual answers are required. This form does not include assessment tasks where students are required or permitted to present their results as collaborative work. Nor does it preclude collaborative effort in research or study for assignments, tests or examinations; but unless it is explicitly stated otherwise, each students answers should be in their own words. If you are not sure if collaboration is allowed, check with your lecturer..
Impersonation is getting someone else to participate in any assessment on your behalf, including having someone else sit any test or examination on your behalf.
Falsiﬁcation is to falsify the results of your research; presenting as true or accurate material that you know to be false or inaccurate.
Use of Unauthorised Materials
Unless expressly permitted, notes, books, calculators, computers or any other material and equipment are not permitted into a test or examination. Make sure you read the examination rules carefully. If you are still not sure what you are allowed to take in, check with your lecturer.
Assisting Others to Commit Academic Misconduct
This includes impersonating another student in a test or examination; writing an assignment for another student; giving answers to another student in a test or examination by any direct or indirect means; and allowing another student to copy answers in a test, examination or any other assessment.
Sample problemSuppose a dermatologist wants to study the effectiveness of two different preparations of a skin lotion using two different forms of application, such as one versus two applications per day. She has 12 patients with a certain skin disease and can apply one form of medication to each arm of each patient. Even though the patients have the same disease, there exists considerable variation among them. The two arms of a patient are expected to respond similarly.
Environmental changesAn ecological experiment at the University of Minnesota, designed to explore the way plant communities will respond to environmental changes which are believed to be occurring on a global scale. The square plots are the experimental units.