Question 1: A clinical trial is run to investigate the effectiveness of an experimental drug in reducing preterm delivery to a drug considered standard care and to placebo.  Pregnant women are enrolled and randomly assigned to receive either the experimental drug, the standard drug or placebo.  Women are followed through delivery and classified as delivering preterm (< 37 weeks) or not.  The data are shown below.

Using this data, generate a 95% confidence interval for the difference in proportions of women delivering preterm in the experimental and standard drug treatment groups. 

Question 2: A study is run comparing HDL cholesterol levels between men who exercise regularly and those who do not.  The data are shown below.

Generate a 95% confidence interval for the difference in mean HDL levels between men who exercise regularly and those who do not. 

Question 3: The following are body mass index (BMI) scores measured in 12 patients who are free of diabetes and participating in a study of risk factors for obesity.  Body mass index is measured as the ratio of weight in kilograms to height in meters squared.  Generate a 95% confidence interval estimate of the true BMI.

   25           27        31        33        26        28        38        41        24        32        35        40

Question 4: A clinical trial is run to evaluate the effectiveness of a new drug to prevent preterm delivery.  A total of n=250 pregnant women agree to participate and are randomly assigned to receive either the new drug or a placebo and followed through the course of pregnancy.   Among 125 women receiving the new drug, 24 deliver preterm and among 125 women receiving the placebo, 38 deliver preterm.  Construct a 95% confidence interval for the difference in proportions of women who deliver preterm. 

Question 5: The following table shows the numbers of patients classified as underweight, normal weight, overweight and obese according to their diabetes status. 

What proportion of diabetics is obese?

Question 6: The following table shows the distribution of BMI in children living in US and European urban neighborhoods.  (The data are in millions.)

What proportion of children is obese and live in a US urban neighborhood?

Question 7: The following table shows the numbers of patients classified as underweight, normal weight, overweight and obese according to their diabetes status. 

What proportion of patients is overweight?

Question 8: What is the best type of graph to display the following data? 

Question 9: What is the best type of graph to display the following data?

GDP per capita fertility rate

   3432.0224      3.783

   6882.4069      4.026

   678.99817      4.508

   3623.5324      2.338

   5741.2071      1.399

   35477.473       1.43

   47548.688       2.04

   691.36909        2.3

   19858.343       1.45

   39152.308      1.994

   2942.4385      3.221

   14623.479      2.175

   4387.7071      2.436

   84732.957       1.52

   3928.8789      2.546

   1455.1022      2.479

   24646.021      2.644

   3056.1185      2.735

Question 10: What is the best type of graph to display the following data? 

Region of country:  New England,New England,South,West,New England, Mid-Atlantic,Mid-Atlantic,New England,New England,South,New England,New England,Midwest,New England,Mid-Atlantic,Mid-Atlantic,New England,West 

Question 11: If we have 95% confidence interval for the mean birth weight of infants born to mothers who smoke (6.3 lbs, 7.2 lbs), that means that the probability that the true mean birth weight for all infants born to mothers who smoke is between 6.3 pounds and 7.2 pounds.

Question 12: We randomize in an experiment in order to ensure that our sample is representative of our population. 

True

False

Question 13: It's impossible for the IQR to be negative.

True

False