**Exercise 7: Checking Ranges and Confidence**

Do you tend to give overconfident answers to questions when you're uncertain? The following questions can help you assess your tendency to provide overconfident estimates. For each question, give your best estimate, and your 80% confidence interval. Thus, for the lower bound, estimate the number for which you judge only a 10% chance exists that the true value is lower, and for the upper bound, estimate the number for which you judge only a 10% chance exists that the true value is higher. You should guess without looking up the answers elsewhere, and only go on to the next step once you've completed answering these questions.

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

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

Best estimate _______ Lower bound _______ Upper bound ________

Once you record your answers, go to the next step