Introductions to Biostatistics Autumn Assignment
Answer all 8 questions.
Question 1 - Classify each variable in this data table as categorical or numeric (otherwise called continuous).
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Patient number
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Sex (1=male, 2=female)
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Age (years)
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Self-reported smoking (cigarettes/day)
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Disability level (0=none, 1=mild, 2=moderate, 3=severe)
|
|
0
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1
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25
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0
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0
|
|
1
|
2
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28
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1
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1
|
|
2
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2
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29
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2
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2
|
|
3
|
1
|
33
|
3
|
3
|
Question 2 -
a. Using the 'fham.p1.RData' data set introduced in tutorial 3 and R Commander, tabulate the relationship between use of blood pressure medications at study entry (bpmeds) and the later occurrence of cardiovascular disease (cvd).
b. Using row or column percentages describe the relationship between current use of blood pressure medications and history of cardiovascular disease.
c. Using conditional probabilities explain why current use of blood pressure medications and history of cardiovascular disease are not independent.
Question 3 -
a. Using the assignment data file allocated to you and R Commander, graph the relationship between MVPA and GPA.
b. Describe in words the relationship between GPA and MVPA hours per week in this data set.
Question 4 -
a. Using the assignment data file allocated to you and R Commander, draw an appropriate graph of MVPA. (Don't forget to provide meaningful labels on your axes).
b. Using the graph alone, describe the centre, spread and shape of distribution of MVPA in these students. (Note: Don't calculate any statistics yet - that is part c).)
c. Use appropriate statistics, to summarise the distribution of MVPA. (Hint: consider measures of centre, spread and shape. Avoid cutting and pasting R commander output - write the answer in your own words.)
Question 5 - It is estimated that 1 in 11 adults (whole world) has diabetes and that 1 in 2 of adults with diabetes are undiagnosed. A random sample of 200 Australian adults were tested for diabetes.
a. If Australian adults do not differ from the rest of the world, what is the probability that our random sample of 200 adults will contain 20 or fewer diabetics?
b. If Australian adults do not differ from the rest of the world, we would predict 10% of all samples to contain fewer than how many diabetics?
c. If Australian adults do not differ from the rest of the world, estimate the mean number of diabetics per sample? Show any working.
Question 6 -
a. If the average age of retirement for the entire population in a country is 64 years and the distribution is normal with a standard deviation of 3.5 years, what is the approximate age range in which 95% of people retire?
b. Last year's graduates from an MPH degree, had a mean first-year income of $62,000 with a standard deviation of $8000. These first year salary levels are known to be normally distributed. What is the approximate percentage of first year graduates who made more than $80000?
Question 7 - Sheila's glucose level one hour after ingesting a sugary drink varies according to the Normal distribution with mean μ=125 mg/dl and standard deviation σ=10mg/dl.
a. If a single glucose measurement is made, what is the probability that Sheila measures above 140 mg/dl?
b. Using the Central Limit Theorem, what is the probability that the sample mean from four separate measurements is above 140 mg/dl? Show any working.
Question 8 - Does this graph show a normal distribution or does it show a binomial distribution? Explain why.
Attachment:- Assignment.rar