Exercise 7: Checking Ranges and Confidence (continued)

OK - time to check your answers. For each question, look at the actual answer and determine whether it falls between your lower bound and your upper bound. If it does, then your uncertainty bounds included the true answer, and you should put a check mark next to that question. If it does not, then your uncertainty bounds did not include the truth, and you should put a circle next to the question. Count the total number of check marks. Since the exercise asked you to give your 80% confidence intervals, you should have 8 of the 10 questions with check marks. If you had fewer than 8 check marks, then this might indicate overconfidence. If you had 9 or 10 of them with check marks then you might not have been confident enough.

1. In the United States in 2002, what percentage of households owned their own home?

Answer: 67.9% (Source: U.S. Census Bureau)

2. In the United States in 1999, out of every 100 live births how many babies weighed less than 1,500 grams?

Answer: 1.45 (Source: National Center for Health Statistics, 2002)

3. In the United States in 1999, what was life expectancy at birth (in years) for females?

Answer: 79.4 years (Source: Health United States, 2002)

4. What percentage of the United States population had Internet access in 2001?

Answer: 54% (Source: United States Census Bureau)

5. In 1999 in the United States, what was the ratio of the number of cancer deaths to the number of heart disease deaths?

Answer: 0.76 (Source: Health United States, 2002)

6. What was the median annual household income in the United States in 2001?

Answer: $42,228 (Source: United States Census Bureau)

7. In 2000 in the United States, what percentage of black males aged 18-24 were smokers?

Answer: 20.8 (Source: Health United States, 2002)

8. How many tons of coal did the United States burn in 2002 to generate electricity?

Answer: 985,374,000 (Source: Electric Power Monthly, United States Department of Energy)

9. In 1998 in the United States, what percent of people were covered by health insurance for the entire year?

Answer: 83.7% (Source: U.S. Census Bureau)

10. How many people died from motor vehicle accidents in the United States in 2000?

Answer: 43,354 (Source: National Vital Statistics Report)