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Department of Mathematics & Statistics

STAT115 Introduction to Biostatistics

Second Semester
18 points

Advances in our understanding of factors which affect health and wellbeing come through research in the health sciences. Examples of such research include:

  • pattern of disease or risk factors for disease such as diet and smoking;
  • studies to identify causes of disease;
  • studies to find out if a newly developed treatment works;
  • studies of factors which may prevent disease such as physical activity;
  • does a cholesterol lowering drug have psychological side effects?;
  • diet factors that enhance or inhibit iron levels in newborn babies;
  • effect of circumcision on HIV/AIDS.

Biostatistics (statistics applied in the health sciences) is a vital tool in the mission to improve health and well-being for all people. STAT115 provides an introduction to the core principles and methods of biostatistics. In this course you will gain an understanding of how statistics is used to answer research questions: How to look for patterns in data, how to test hypotheses about disease causation and prevention and improvement in well-being. The program R will be used throughout the paper for data summary and statistical analysis. The understanding and skills gained in STAT115 can be a starting point for a career in biostatistics or can be used to assist understanding of research in other disciplines including epidemiology, physiology, anatomy, human nutrition, sports science and psychology.

Paper details

Topics covered include an introduction to the research process, data exploration and measures for describing data, introduction to probability, binomial and normal distributions, estimation and confidence intervals, hypothesis testing, categorical data, simple linear regression, control of confounding, statistical issues in study design, and analysis of variance. Data analysed in the paper are primarily from areas dealing with the human population. Special care is taken to integrate the statistical methodology during the semester with study design principles.

Potential students

This paper is intended for all students specializing in health sciences subjects such as nutrition, anatomy, genetics, epidemiology, sports science, psychology and the biomedical sciences in general. But it can also be taken by those who wish to specialize in statistics. The parallel paper taught in semester 1, STAT 110 Statistical Methods, is for students in the biological and some of the social sciences. STAT 115 serves as a pre-requisite for all subjects which have STAT 110 as a pre-requisite. It will serve as an alternative to QUAN 101, BSNS102 or STAT 110 in the commerce core when it has been passed before enrolling for a BCom degree or when enrolling for a BCom and another degree for which STAT 115 is appropriate.

Main topics

  • Basic measures for describing data
  • Introduction to statistical program R
  • Introduction to probability
  • Binomial and normal distributions
  • Estimation and confidence intervals
  • Hypothesis testing
  • Categorical data analysis
  • Simple linear regression
  • Regression procedures and the control of confounding
  • The analysis of variation (ANOVA)
  • Statistical issues in study design and critical appraisal of research



Required text


A copy of the course slides, is available electronically on the Resources page - click on Resources box at top of this page.

This is also available for purchase through the University Print Shop located in the Central Library.



Four 50 minute lectures per week; Monday, Tuesday, Wednesday, Thursday at 8am or 10am. There is no preliminary lecture for this course.


Tutorials are cafeteria style, in that students are free to attend at any scheduled tutorial time. They will run in room MA124 (Level 1, Science III).

Internal Assessment

There will be seven assignments and three tests, dates can be found on the course schedule on the Resources page. Exact total marks will vary, but the first six assessment will be scaled to have a mark recorded out of 20 and the final assignment will be out of 40. The tests contribute 2/3 of your internal score, with the remaining 1/3 being contributed by your assignment marks.

Assessments will be conducted on-line with tests completed in room MA124 computer laboratory (Level 1 of the Science III building). Note that whereas your assignments can be accessed, worked on and submitted from any computer with an internet connection, you must be on campus to complete your tests in the MA124 laboratory. If you are submitting assignments from outside the lab, it is a good idea to make sure you have been to the lab to check that your log-ins work correctly before the first test.

You can check your marks by logging in to your Personal Resources from the Resources page.

Exam format

A three-hour multiple choice exam.

Final mark

Your final mark F in the paper will be calculated according to this formula:

F = max(E, (6E + A + 2T)/9)


  • 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

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.

Further information

While we strive to keep details as accurate and up-to-date as possible, information given here should be regarded as provisional. Individual lecturers will confirm teaching and assessment methods.

Examples of studies relevant to Stat115

Recent research has investigated risk factors for melanoma. The study involved office workers and farm workers and the history of sunburn in both groups, as well as possible confounding factors such as the reaction of the skin to sun exposure, hair colour, skin freckling and the number of moles on the upper arm. Studies of this type are discussed in STAT115.
Another study reports the current prevalence of obesity and body fat distribution in the New Zealand population, and investigates whether there is a trend to increasing obesity. Body weight, height, skinfold, and waist and hip circumference were measured on 4420 New Zealanders as part of the 1997 National Nutrition Survey. The results are compared with data from 3300 people in the 1989 Life in New Zealand Survey.

There is evidence that body weight and body mass index have increased in recent years, that there is an increasing trend towards obesity, and that the proportion of the population likely to exhibit health risks is also increasing.
A study investigated the relation of infant feeding practice to childhood respiratory illness, growth, body composition and blood pressure. The health of 674 infants was measured by considering respiratory illness, weight, height, percentage of body fat, and blood pressure, in relation to the duration of breast feeding and the timing of the introduction of solids.

Some key findings from the study were: