{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

statsexam3f06sol

# statsexam3f06sol - Economic Statistics Exam 3 Last name...

This preview shows pages 1–3. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
3. A database contains the fuel efficiency ( in terms of miles per gallon ) of seventeen car models. These values are: 18.6 19.9 20.5 32.8 19.2 20.2 20.6 36.1 19.4 20.2 20.8 36.1 19.4 20.5 25.1 39.4 43.1 Construct a box - and - whisker plot to describe this data. The box goes from 19.9 ( the 25 th percentile ) to 32.8 ( the 75 th percentile ) , with a vertical line at 20.5 ( the median ) . The whiskers extend to 18.6 and 43.1. 4. The starting salaries of economics majors are distributed with a mean of \$ 35,000 and a standard deviation of \$ 5,000. With this information ( and no additional assumptions! ) , calculate the fraction of salaries between \$ 25,000 and \$ 45,000. According to Chebyshev’s Theorem, at least ( 1 ! 1 k 2 ) fraction of observations lie within k standard deviations of the mean. In this problem, \$ 25,000 is two standard deviations below the mean and \$ 45,000 is two standard deviations above, so at least ( 1 ! 1 2 2 ) = 3 4 of observations are within this range. 5. On any given day, it can be sunny or rainy, and it can be cold or warm. There is a 0.30 chance that it is rainy; there is a 0.20 chance that it is cold; and there is a 0.25 chance that it is both rainy and cold. What is the probability that it is cold or rainy ( or both ) ? P [cold or rain] = P [cold] + P [rain] ! P [cold and rain] = 0 . 30 + 0 . 20 ! 0 . 25 = 0 . 25 ( As a note, the probabilities in the problem are impossible. Oops. ) 6. The Center for Disease Control estimates that about 1 in 300 Americans is infected with HIV. There is a rapid test for HIV, which is fairly accurate. Among people with the virus, 99 of 100 tests are positive; among people without the virus, 1 out of 200 tests results in a ( false ) positive. If someone takes the test and gets a positive result, what is the chance that he is infected with the virus?
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 12

statsexam3f06sol - Economic Statistics Exam 3 Last name...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online