Math 105 Graded Homework 4
Name _________________________________
Due Wednesday, February 17. Show your work. Simplify each answer. Draw a box
around each answer.
Average Annual Consumer Price Index (All urban consumers CPI-U)
Year CPI
(Base year: 1982-1984 = 100)
1975 53.8
1980 82.4
1985 107.6
1990 130.7
1995 152.4
2000 172.2
2005 195.3
1. In 1980 my annual income was $19,000. What did my income need to be in 2005 to
maintain the same standard of living?
2. What is the overall rate of inflation from 1995 to 2005?
The next problems concern a test for a disease. A positive test indicates that the disease is
present. A follow-up shows the following data for 3700 cases in a certain study:
Disease
No disease
Total
Test positive
75
570
645
Test negative
10
3045
3055
3. In the study, how many cases were false positives?
4. In this study how many cases were true negatives?
5. In what fraction of cases with positive tests did the patient actually have the disease?
Give your answer as a percent.
6. In what fraction of cases in which the patient actually had the disease did the test indicate
that the disease was present? Give your answer as a percent.