MAT5212 Biostatistics Assignment Brief

Submission Guidelines

• Full marks will be gained by complete solutions to all questions. Marks for each question are given.
• Answer the questions in the order given and start each question (not each part of a question) on a new page.
• Be clear and concise. Show all of your working. Answers to the Biostatistics assignment problems need to be written up in grammatically correct English. Failure to do so will result in deduction of marks.
• The assignment solutions must be your own work. Each submission from your assignment must have a completed coversheet attached and be submitted on or before the due date. You are reminded of the declaration:
  "I certify that the attached assignment is my own work and that any material drawn from other sources has been acknowledged".
  that you sign when you complete the coversheet.
• You may use a spreadsheet program such as Microsoft Excel to aid in your calculations. If you choose to use a spreadsheet program for any part of the assignment, then this must be clearly stated and a printout of the relevant session  must be submitted with the written work.
• In the interests of fairness, extension of time for submission of the assignment questions will be given only in exceptional circumstances, and then only in accordance with University rules (see page 2).
• The deadline for Assignment 1 is 12:00 pm on Friday 8th of April 2016. You may hand in your completed work directly to Aiden Fisher in JO 19.346 (or in class) in hardcopy form or online students may email their assignments to a.fisher@ecu.edu.au. All late submissions are penalised in accordance to ECU guidelines.
• Assignment – Part 1 is marked out of 45 and contributes 15 % to your overall grade.

Conditions for Assignment Extension

In accordance with ECU policy, extensions are given on the following grounds and must include all appropriate supporting documentation:

• Ill health or injury for an extended period of time – medical certificate is required;
• Compassionate grounds – supporting documentation includes e.g. newspaper notice plus other evidence if not the same family name, e.g. marriage certificate;
• Representation in sporting activities at a national or international level;
• Representation in significant cultural activities;
• Employment related intrastate, interstate and overseas travel – a letter from your employer, including your supervisors’ full contact details.

The following factors will not be considered as grounds for extension:

• Routine demands of employment;
• Stress or anxiety normally associated with examinations, required assessments or any aspect of course work;
• Routine financial support needs;
• Lack of knowledge of the requirements of academic work;
• Difficulties with English language;
• Scheduled anticipated changes of address, moving home etc;
• Demands of sport, clubs, social or extra-curricular activity other than those specified above;
• Recreational travel (domestic or international);
• Planned events such as weddings, birthday parties etc;
• Misreading the deadline.

Question 1

Before generic drugs can go to market it needs to be shown that they are bioequivalent to the name- brand drug they intimidate. Suppose that below are the results from one such trial, showing the time in minutes between when the drug was administered in tablet form until the peak bioavailability of the active compound.

1. Find the sample mean and standard deviation of the time until peak bioavailability for both the name-brand and generic drugs.
2. Use the appropriate test to determine whether the generic drug has the same mean time until peak bioavailability as the name-brand drug, assuming that the times for both drugs are normally distributed and have equal variance.
3. Find the 95% confidence interval for the mean difference in times assuming equal variance.
4. Perform the calculations in parts (b) and (c) again this time assuming unequal variances with degrees of freedom ???? = 11.833 (round down to 11 if using tables). How does the conclusion  of the test differ?
5. Without doing any further tests which of the two results should be used? Give reasons for your answer.

Question 2

[Daniel 8th edition] Researchers have observed a greater airways resistance in smokers than non- smokers. Suppose a study conducted to compare the percentage of tracheobronchial retention of particles in smoking discordant monozygotic twins yielded the following results:

1. Find the sample mean and standard deviation of the percentage of particle retention for the smoking and non-smoking twins.
2. What is the appropriate test for testing if there is a difference in the means of the two data sets? Explain your reasoning.
3. Use the test you chose in (b) to determine if there is a difference between the mean percentage of particle retention for the smoking twins and the non-smoking twins, using a significance level of ???? = 0.05. How does the answer change if a stricter significance level of ???? = 0.01 is used for the test instead?
4. From the following SPSS output what can be concluded about the distribution of the two data sets? Is this consistent with the assumptions of the test you chose in part (b)?

QUESTION 3

A common concern with the administration of drugs is that the patient becomes tolerant to the drug with repeated treatments and thus requires progressively stronger doses. A study was done using methadone, a synthetic opioid similar to morphine, to see whether patients would become tolerant after three treatments. The patients’ euphoria levels (their perceived reduction in pain) were scored after each administration of the drug and the results are shown in the table below:

1. Find the sample mean and standard deviation of the euphoria scores for each treatment.
2. Use the appropriate test and determine whether there is a difference in the means of the euphoria scores for each successive treatment. What can be concluded from this test?
3. Below is the output from SPSS of multiple post-hoc tests. Which outputs are appropriate for testing the assumption of the test used in part (b)? What are the conclusions of these tests?