Exam 11: Confidence Intervals for Proportions

Consider the following to answer the question(s) below: EU (European Union) countries report that 46% of their labour force is female. The United Nations wants to determine if the percentage of females in the Canadian labour force is the same. Representatives from Statistics Canada plan to check a random sample of over 10,000 employment records on file to estimate the percentage of females in the Canadian labour force. -They actually select a random sample of 525 employment records, and find that 229 of the people are females. Construct the 90% confidence interval.

Consider the following to answer the question(s) below: EU (European Union) countries report that 46% of their labour force is female. The United Nations wants to determine if the percentage of females in the Canadian labour force is the same. Representatives from Statistics Canada plan to check a random sample of over 10,000 employment records on file to estimate the percentage of females in the Canadian labour force. -They actually select a random sample of 525 employment records, and find that 229 of the people are females. The 90% confidence interval is

A study was recently conducted at a major university to estimate the difference in the proportion of business school and non-business school graduates who go on to a higher degree programme within five years of graduation A random sample of 400 business school graduates showed that 75 had gone to graduate school, while in a random sample of 500 non-business graduates, 137 had done so. The standard error for the difference in the proportions of the two groups is

Consider the following to answer the question(s) below: One division of a large defense contractor manufactures telecommunication equipment for the military. This division reports that 12% of non-electrical components are reworked. Management wants to determine if this percentage is the same as the percentage rework for electrical components manufactured by the entire company. The Quality Control Department plans to check a random sample of the over 10,000 electrical components manufactured across all divisions. -They actually select a random sample of 450 electrical components and find that 46 of those had to be reworked. Create the 99% confidence interval.

All else being equal, increasing the level of confidence desired will

Which of the following is not an assumption / condition required for constructing a confidence interval for the proportion?

Consider the following to answer the question(s) below: EU (European Union) countries report that 46% of their labour force is female. The United Nations wants to determine if the percentage of females in the Canadian labour force is the same. Representatives from Statistics Canada plan to check a random sample of over 10,000 employment records on file to estimate the percentage of females in the Canadian labour force. -Are the assumptions and conditions for constructing a confidence interval met? Explain.

City officials want to estimate the proportion of visitors who are repeat visitors to the Rideau Canal Skateway. They take a sample of 400 visitors and find that 100 are on a second visit. The 99% confidence interval is 0.1942 to 0.3058. The correct interpretation of the interval is

Consider the following to answer the question(s) below: One division of a large defense contractor manufactures telecommunication equipment for the military. This division reports that 12% of non-electrical components are reworked. Management wants to determine if this percentage is the same as the percentage rework for electrical components manufactured by the entire company. The Quality Control Department plans to check a random sample of the over 10,000 electrical components manufactured across all divisions. -The 95% confidence interval based on this data is 0.0742 to 0.1302. Which of the following is the correct interpretation?

Consider the following to answer the question(s) below: One division of a large defense contractor manufactures telecommunication equipment for the military. This division reports that 12% of non-electrical components are reworked. Management wants to determine if this percentage is the same as the percentage rework for electrical components manufactured by the entire company. The Quality Control Department plans to check a random sample of the over 10,000 electrical components manufactured across all divisions. -They actually select a random sample of 450 electrical components and find that 46 of those had to be reworked. The 99% confidence interval is

Based on the 95% confidence interval, should the Quality Control Department conclude that the percentage of rework for the electrical components is lower than the rate of 12% for non-electrical components?

Consider the following to answer the question(s) below: EU (European Union) countries report that 46% of their labour force is female. The United Nations wants to determine if the percentage of females in the Canadian labour force is the same. Representatives from Statistics Canada plan to check a random sample of over 10,000 employment records on file to estimate the percentage of females in the Canadian labour force. -Interpret the confidence interval in this context.