Stratford University Week 7 Confidence Interval Maths Discussion Problems

A. Week 7 Post (300+ words):

Give an example of an interval estimate of an average or proportion you may use in your daily life. For instance, you may say that you are pretty sure your average commute time is between 25-30 minutes, or you are fairly confident that between 60-65% of the population love dogs. Collect some data to see how well your intuition is working. First, does your sample data meet all assumptions necessary to construct the confidence interval of the type you need? Even if it doesn’t, construct and interpret the confidence interval.

B.

1. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

A survey of 865 voters in one state reveals that 408 favor approval of an issue before the legislature. Construct the 95% confidence interval for the true proportion of all voters in the state who favor approval.

2. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

Of 260 employees selected randomly from one company, 18.46% of them commute by carpooling. Construct a 90% confidence interval for the true percentage of all employees of the company who carpool.

3. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

Of 346 items tested, 12 are found to be defective. Construct the 98% confidence interval for the proportion of all such items that are defective.

4. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

A survey of 300 union members in New York State reveals that 112 favor the Republican candidate for governor. Construct the 98% confidence interval for the true population proportion of all New York State union members who favor the Republican candidate.

5. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

When 328 college students are randomly selected and surveyed, it is found that 122 own a car. Find a 99% confidence interval for the true proportion of all college students who own a car.

6. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

Of 92 adults selected randomly from one town, 61 have health insurance. Find a 90% confidence interval for the true proportion of all adults in the town who have health insurance.

7. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

Of 380 randomly selected medical students, 21 said that they planned to work in a rural community. Find a 95% confidence interval for the true proportion of all medical students who plan to work in a rural community.

8. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

Of 118 randomly selected adults, 34 were found to have high blood pressure. Construct a 95% confidence interval for the true percentage of all adults that have high blood pressure.

9. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

A study involves 607 randomly selected deaths, with 35 of them caused by accidents. Construct a 98% confidence interval for the true percentage of all deaths that are caused by accidents.

10. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

Of 150 adults selected randomly from one town, 30 of them smoke. Construct a 99% confidence interval for the true percentage of all adults in the town that smoke.