Question

According to a Field Poll, 400 out of 506 surveyed California adults feel that “education and our schools” is one of the top issues facing California. We wish to construct a 90% confidence interval for the true proportion of California adults who feel that education and the schools are one of the top issues facing California.

1. A point estimate for the true population proportion is: _______________

(Write as a decimal and round to 4 decimal places)

2. The margin of error for a 90% confidence level is: _________________

(Write as a decimal round to 4 decimal places)

3. A 90% confidence interval for the population proportion is:

(Write as a decimal round to 4 decimal places.)

4. If we changed to an 85% confidence level, what would happen to your confidence interval and your margin of error? Does the confidence interval get wider or more narrow? Does the margin of error increase or decrease?

5. If we changed to a 95% confidence level, what would happen to your confidence interval and your margin of error?  Does the confidence interval get wider or more narrow? Does the margin of error increase or decrease?

6. Five hundred eleven (511) homes in a certain southern California community are randomly surveyed to determine if they meet minimal earthquake preparedness recommendations. One hundred seventy-three (173) of the homes surveyed met the minimum recommendations for earthquake preparedness and 338 did not.

Find the confidence interval at the 90% Confidence Level for the true population proportion of southern California community homes meeting at least the minimum recommendations for earthquake preparedness.

(Write as a decimal and round to the 4th decimal place)

7. State the previous confidence interval in the form of p'±E.

(Write as a decimal and round to the 4th decimal place)

8. Five hundred eleven (511) homes in a certain southern California community are randomly surveyed to determine if they meet minimal earthquake preparedness recommendations. One hundred seventy-three (173) of the homes surveyed met the minimum recommendations for earthquake preparedness and 338 did not.

The point estimate for the population proportion of homes that do not meet the minimum recommendations for earthquake preparedness is _____________.

(Write as a decimal and round to the 4th decimal place)

9. What is meant by the term “90% confident” when constructing a confidence interval for a proportion?

	A.	If we took repeated samples, the sample proportion would equal the population mean in approximately 90% of the samples.
	B.	If we took repeated samples, approximately 90% of the confidence intervals calculated from those samples would contain the sample proportion.
	C.	If we took repeated samples, approximately 90% of the samples would produce the same confidence interval.
	D.	If we took repeated samples, approximately 90% of the confidence intervals calculated from those samples would contain the true value of the population proportion.

Answer 1