This preview shows pages 1–2. Sign up to view the full content.
HW 2 (from 3
rd
ed. of text)
1. 3.11. Suppose that a medical test has a 92% chance of detecting a disease if the person has it
(i.e. 92% sensitivity) and a 94% chance of correctly indicating that the disease is absent if the
person really does not have the disease (i.e. 94% specificity). Suppose that 10% of the
population has the disease.
What is the probability that a randomly chosen person will test positive?
What is the probability of having the disease given a positive test?
2. 3.13. The following data table is taken from a study of the relationship between health risk
and income using a large group of people living in Massachusetts. Here "stressed" means the
person reported that most days are extremely stressful or quite stressful; "not stressed" means
that the person reported that most days are a bit stressful, not very stressful, or not at all
stressful.
Low
Medium
High
Total
Stressed
526
274
216
1016
Not Stressed
1954
1680
1899
5533
Total
2480
1954
2115
6549
Use the table to answer the following questions.
a. What is the probability that someone in this study is stressed?
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 12/13/2011 for the course STAT 205 taught by Professor Hendrix during the Fall '09 term at South Carolina.
 Fall '09
 Hendrix

Click to edit the document details