14. An article in a Florida newspaper reported on the topics that teenagers most want to discuss with their parents.

Results of poll:

46% would like more discussion about the family's financial situation

37% would like to talk about school

39% would like to talk about religion

Percentages were based on a national sampling of 513 teenagers.

Estimate the proportion of all teenagers who want more family discussions about school.

Use a 90% confidence level.

**Solution: **The 90% confidence interval is

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15. A new cigarette has been marketed.

FDA tests on cigarette:

Mean nicotine content: 28.7 milligrams

Standard deviation: 2.4 milligrams

for a Sample of n = 9 cigarettes

Construct a confidence interval for the mean nicotine content of this brand of cigarette.

**Solution: **The 95% confidence interval is

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16. Desiring to purchase a new car. Point to consider: resale value of the car after 5 yrs. of ownership. I decide to estimate the resale value of the car with a 99% confidence interval. You manage to obtain data on 17 recently resold 5-year old foreign sedans of that model. The 17 cars were resold:

At an avg. price of $12,700

Standard deviation: $600

What is the correct form of a 99% confidence interval for the true mean resale value of a 5-year old specific foreign sedan?

**Solution: **The 99% confidence interval is

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