The Cardiac.mtw Minitab file is from a study which was conducted to determine whether a drug called "Dobutamine" could be used effectively in a test for measuring a patient's risk of having a heart attack. For younger patients, a typical test of this risk is called "Stress Echocardiography" which involves raising the patient's heart rate by exercise and then taking various measurements, such as heart rate and blood pressure. This test cannot be used on older patients where their bodies cannot take the stress of hard exercise. The key to assessing risk, however, is putting stress on the heart before taking the relevant measurements. While exercise can't be used to create this stress for older patients, the drug Dobutamine can. This study was used to see whether the stress echocardiography test was still effective in predicting cardiac events when the stress on the heart was produced by Dobutamine instead of exercise.
Source: Garfinkel, Alan, et. al. "Prognostic Value of Dobutamine Stress Echocardiography in Predicting Cardiac Events in Patients With Known or Suspected Coronary Artery Disease." Journal of the American College of Cardiology 33.3 (1999) 708-16.
Some of the variables of interest recorded in Cardiac.mtw are:
Variable Name Variable Description
ID Patient identifying number
BHR Basal heart rate (beats per minute)
BBP Basal blood pressure (beats per minute)
Dose Dose of Dobutamine given (ml)
MaxHR Maximum heart rate (beats per minute)
MaxBP Maximum blood pressure (beats per minute)
Age Patient’s age
Sex Patient’s gender (male = 0, female = 1))
ChestPain The patient experienced chest pain (0 = no, 1 = yes)
HDiabetes The patient has a history of diabetes (0 = no, 1 = yes)
HSmoking The patient has a history of smoking (0 = no, 1 = yes)
Use the Minitab worksheet to answer the questions on the following page. Follow the instructions below in your answers:
· Where a question asks for a percentage, the answer should be expressed as a value between 0% and 100%. Where a question asks for a proportion, the answer should be expressed as a value between 0 and 1. Give answers to the number of decimal places specified in each part.
· Descriptive statistics for parts i. and j. can be calculated in Minitab but you will need to select the appropriate statistics from the Statistics option after selectingDisplay Descriptive Statistics.
· For part k., ensure that all Minitab output has is clearly labelled (ie. Group 1, 2, 3 and 4 are not informative labels).
a. How many of the patients in the study experienced chest pain? (integer)____________
b. How many of the females in the study experienced chest pain? (integer)____________
c. What percentage of the patients had a history of smoking? (2dp)__________________
d. What percentage of the males had a history of smoking? (2dp)____________________
e. What proportion of the subjects had both a history of diabetes and a history of smoking? (2dp)__________________________________________________________
Question 4 continued
f. What was the mean basal heart rate of the subjects in the study (2dp)____________
g. What was the median age of the patients who experienced chest pain (2dp)__________
h. What was the standard deviation of the maximum heart rates recorded on the males in the study (2dp)__________________________________________________________
i. What was the range of ages for the subjects who were given the highest dose of Dobutamine? (integer)_____________________________________________________
j. What was the interquartile range of the maximum blood pressures recorded on the subjects who were given the second highest dost of Dobutamine?(2dp)______________
k. Consider the research question:
Are patients with a history of diabetes more likely to experience chest pain?
Use Minitab to construct appropriate graphical and numerical summaries to address this research question. Use your summaries to comment on the research question.
