Questions -

QUESTION 1 - A container has 2 red marbles and 8 blue marbles. If one marble is selected randomly, then the probability of obtaining a red marble is 2/8 or 0.25.

True

False

QUESTION 2 - Suppose we wish to estimate the prevalence of a condition which we expect to be around 24%. What sample size do we need if we can accept a margin of error = e of 1%.

Please specify your answer as a whole number. Hint: If your answer is not a whole number then you will need to round up to the nearest whole number.

QUESTION 3 - According to Central Limit Theorem, as sample sizes decrease

Sample means stay similar to the population mean

Standard error of means increases in proportion to the inverse of the square root of the sample size

A histogram of sample means will approximately follow a Normal distribution

All of the above

QUESTION 4 - As the power of a test increases, what happens to the probability of a Type II error?

Stays the same

Increases

Decreases

It depends on the sample size

QUESTION 5 - After a campaign to encourage students to take precautions against skin cancer, in a certain high school class consisting of 27 girls and 38 boys, it is observed that 16 girls and 33 boys take precautions as measured by a survey to elicit how often they wear sunscreen, sunglasses and hats for protection against the sun.

Please use this information to calculate the probabilities for the following questions. Please provide each numerical answer to TWO DECIMAL places (X.XX) with no additional information in the answer box. Just X.XX (i.e. no extra spaces, no units, etc).

What is the probability that a student picked at random takes precautions against skin cancer (by wearing sunscreen, sunglasses and a hat)?

QUESTION 6 - After a campaign to encourage students to take precautions against skin cancer, in a certain high school class consisting of 22 girls and 35 boys, it is observed that 14 girls and 14 boys take precautions as measured by a survey to elicit how often they wear sunscreen, sunglasses and hats for protection against the sun.

Please use this information to calculate the probabilities for the following questions. Please provide each numerical answer to TWO DECIMAL places (X.XX) with no additional information in the answer box. Just X.XX (i.e. no extra spaces, no units, etc).

What is the probability that a student picked at random takes precautions against skin cancer (by wearing sunscreen, sunglasses and a hat), given that the student is a boy?

QUESTION 7 - A WHO auditor is given an assignment to choose and audit 26 countries. She lists all countries whose name begins with A, assigns each a number, and uses a random number table to pick one of these numbers and thus one country. She proceeds to use the same procedure for each letter of the alphabet and then combines the 26 results into a group for auditing. Which of the following are true statements?

I. Her procedure makes use of chance.

II. Her procedure results in a simple random sample.

III. Each country has an equal probability of being selected.

I and II

I and III

II and III

I, II and III

None of the above gives the complete set of true responses.

QUESTION 8 - What are essential components of good data management?

a. A well documented codebook

b. Includes detailed written protocols for procedures like data verification

c. Validating data

d. Hard copy and electronic backups

e. All of the above (a, b, c and d)

f. None of the above (a, b, c or d)

QUESTION 9 - Determining the sample interval (represented by k), randomly selecting a number between 1 and k, and including each kth element in your sample are the steps for which form of sampling?

Stratified Random

Sampling

Systematic Sampling

Simple Random Sampling

Cluster sampling

QUESTION 10 - The animal colony at a hospital contains 37 male rats and 19 female rats. Of the 19 females, 4 are white and 15 spotted. Of the 37 males, 8 are white, and 29 are spotted. Suppose that you randomly select 1 rat from this colony.

What is the probability, as a proportion, of obtaining a white male?

Write your answer to TWO DECIMAL PLACES: X.XX

QUESTION 11 - The animal colony at a hospital contains 35 male rats and 20 female rats. Of the 20 females, 3 are white and 17 spotted. Of the 35 males, 24 are white, and 11 are spotted. Suppose that you randomly select 1 rat from this colony.

What is the probability, as a proportion, of obtaining a female given the rat you have just sampled is spotted?

Write your answer to TWO DECIMAL PLACES: X.XX.

QUESTION 12 - Suppose we wish to compare the mean systolic blood pressure in two groups of patients using a two-sided t-test at the 5% level. We wish to detect a diference of 15 mmHg between groups of subjects allocated to each group at random with a 85% power. The population standard deviation is taken to be 25 mmHg.

Assuming equal numbers in each group, how many subjects are required in each group?

QUESTION 13 - Having consumed no alcohol in the last ten days and having consumed some alcohol in the last ten days is a __________.

a. mutually exclusive event

b. independent event

c. conditional event

d. None of the above

QUESTION 14 - NHMRC established the Community and Consumer Advisory Group (CCAG) to provide timely, high level, strategic advice to the National Health and Medical Research Council (NHMRC), including its Council and Principal Committees, on health matters and on health and medical research matters from a consumer and community perspective.

True

False

QUESTION 15 - 100 trials were conducted worldwide to investigate whether an online reminder service could improve adherence to taking medication despite some unpleasant side effects. Assuming significance tests were conducted at a significance level of 0.05 (so we reject if p< 0.05) independently for each trial and that the null hypothesis is actually true, how many of these studies would we expect to incorrectly find a significant result?

Note: Round your answer to the nearest whole number (X or XX or XXX etc).

QUESTION 16 - Which statements are true about complex sampling involving clustering compared to simple random sampling?

Complex sampling may increase logistic efficiency

Complex sampling increases statistical efficiency

Complex sampling decreases statistical efficiency

To retain the same Confidence Interval Width as SRS you need to decrease the sample size.

QUESTION 17 - In relation to the quality of data entry options, with respect to databases (such as EpiInfo, Access) and spreadsheets (such as Excel), which of the following statements are true?

Please choose all true statements with respect to the question.

A spreadsheet can include both numeric and character fields, whereas a database cannot

A database is more structured than a spreadsheet

A database can prevent out-of-range values being entered

A spreadsheet can be used to carry out statistical analysis

To avoid entering wrong categories, a spreadsheet can often be set up to accept specified categories via a 'drop down list'

QUESTION 18 - A diagnosis for a test is such that it (correctly) detects the disease in 95% of the individuals who actually have the disease. Also, if a person does not have the disease, the test will report that he or she does not have it with probability 0.93. Only 4% of the population has the disease in question. If a person is chosen at random from the population and the diagnostic test indicates that he or she has the disease, what is the conditional probability that the person does, in fact, have the disease?

Provide your numerical answer to THREE DECIMAL PLACES: X.XXX.

QUESTION 19 - As the lead researcher working with an Indigenous community, at what stage of the project should you determine who owns the research data and who will have access the research outcomes?

This is not an important consideration and so there is no requirement to consider this until after the research has finished.

At the start of the project you should identify and consult all key individuals and groups involved, to determine who owns and can access the research results.

Once you have gained free, prior and informed consent, you or your research institution will own the data. The research outcomes can be presented to the community of interest at the end of the project.

Consent is an on-going process, so this can happen at any stage of the project.

QUESTION 20 - A two-stage cluster sample involves selecting:

A. A random sample of individuals

B. A simple random sample of clusters

C. A simple random sample of individuals

D. A and B but not C

E. C and B but not A