Practice Test

The dataset used for your projectconsisted of 588 patients who underwent a typical test for identifying risk of a patient having a heart attack is called "stress echocardiography." Patients were instructed to exercise (typically this involves the patient running on a treadmill), and measurements such as heart rate and blood pressure are recorded. Treadmill exercise is not always ideal for the older patient, and therefore an alternative means of putting stress on the heart is necessary. The drug dobutamine was utilized in this study to artificially place stress on the heart and measurements were recorded. This study attempted to determine if dobutamine-related stress echocardiography was an effective means of predicting a cardiac event.Some of the variables collected were:

VariableDescription and Code

Ididentification number

basebp

basal blood pressure

pkhr

peak heart rate

dp

double product (= pkhr x sbp)

dose

dose of dobutamine given (10, 15, 20, 25, 30, 35 or 40 mcg/kg/min)

age

age

gender

gender (male = 0, 1=female)

baseef

baseline cardiac ection fraction (a measure of the heart's pumping efficiency)

dobef

ection fraction on dobutamine

newmi

cardiac event, new myocardial infarction, or heart attack (0=no, 1= yes)

For questions 1.a thru 1.e below, discuss a possible statistical approach, including specific test(s), that you might use to examine the question. Identify the null and alternative hypothesis for that test and justify your choice of test. Indicate any plots or frequency tables that might be helpful in examining the question.

1. a. (4 points) Theejection fractionrefers to the amount of blood that is pumped (or ejected) out of the ventricles with each contraction of the heart. Is ejection fraction on dobutamine (dobef) associated with gender?

Approach

Null and alternative hypothesis:

Justify choice of test:

Plots or tables:

1.b. (4 points) Is gender associated with new myocardial infarction (newmi)?

Approach

Null and alternative hypothesis:

Justify choice of test:

Plots or tables:

1.c.(4 points) Is ejection fraction on dobutamine (dobef) associated with dose?

Approach

Null and alternative hypothesis:

Justify choice of test:

Plots or tables:

1.d.(4 points) Is there a linear association between ejection fraction on dobutamine (dobef) and age?

Approach

Null and alternative hypothesis:

Justify choice of test:

Plots or tables:

1.e.(4 points) Is there a linear association between ejection fraction on dobutamine (dobef) and age after accounting for gender and dose?

Approach

Null and alternative hypothesis:

Justify choice of test:

Plots or tables: