MPH501 2020 January Module 3 Exercise Latest

MPH501 Quantitative Methods for Public Health Application

Module 3 Exercise

Question 1Hyperlipidemia in children has been hypothesized to be related to high cholesterol in their parents.  The following data were collected on parents and children.

CHILD    Both Parents Hyperlipidemic         One Parent Hyperlipidemic            Neither Parent Hyperlipidemic

Not Hyperlipidemic          13           34           83

Hyperlipidemic   45           42           6

a.            What is the probability that one or both parents are hyperlipidemic?

b.            What is the probability that the child and both parents are hyperlipidemic?

c.            What is the probability that a child is hyperlipidemic IF neither of his/her parents are hyperlipidemic?

d.            What is the probability that a child is hyperlipidemic IF both of his/her parents are hyperlipidemic?

Question 2 A national survey of graduate students is conducted to assess their consumption of coffee.  The following table summarizes the data.

               Do not drink coffee          Drink Decaffeinated Only              Drink Caffeinated Coffee

Male      145        94           365

Female  80           121        430

a.            What proportion of students drink decaffeinated coffee only?

b.            What proportion of coffee drinkers (caffeinated and decaffeinated) are female?

c.            What proportion of the females do not drink coffee?

Question 3 Investigators wanted to assess the accuracy of self-reported smoking status.  Participants are asked whether they currently smoke or not.  In addition, laboratory tests are performed on hair samples to determine presence or absence of nicotine.  The laboratory assessment is considered the gold standard, or truth about nicotine.  The data are as follows:

               Nicotine Absent Nicotine Present

Self-Reported Non-Smoker           82           14

Self-Reported Smoker     12           52

a.            What is the sensitivity of self-reported smoking status?

b.            What is the specificity of self-reported smoking status?

Question 4 The following table displays blood pressure status by sex.

               Optimal Normal Hypertension      Total

Male      22           73           55           150

Female  43           132        65           240

Total      65           205        120        390

a.            What proportion of the participants have optimal blood pressure?

b.            What proportion of men have optimal blood pressure?

c.            What proportion of participants with hypertension are male?

d.            Are hypertensive status and male gender independent?

Question 5 Suppose BMI at 16 weeks gestation has a mean 28.5 with a standard deviation of 3.6 and BMI is assumed to follow a normal distribution.  Find the following:

a.            The proportion of women with BMI> 30.

b.            The proportion of women with BMI>40.

c.            The BMI that separates the top 10% from the rest.

Question 6 Diastolic blood pressures are approximately normally distributed with a mean of 75 and a standard deviation of 10.

a.            What is the 90th percentile of diastolic blood pressure?

b.            If we consider samples of 20 patients, what is the 90th  percentile of the mean diastolic blood pressure?