QMS 230 Review Questions
Question 1.
Ryerson Automobile Insurance Company wants to estimate the mean time it takes for workers who are employed in downtown Toronto to get to work. A sample of 10 workers reveals the following number of minutes traveled. 38 33 21 45 34 57 46 62 25 40
It is known that the time it takes for all workers who are employed in downtown Toronto to get to work is normally distributed.
a. Determine the critical value(s) of a 91.5% confidence interval for the mean time it take for all workers who are employed in downtown Toronto to get to work
b. Construct a 91.5% confidence interval for the mean time it take for all workers who are employed in downtown Toronto to get to work. Interpret the result
Question 2.
In order to estimate the marketing officer’s dinner expenses when out of town on business, the office accountant took a random sample of dinner meal receipts and obtained the following results:
$23.80 36.50 28.75 21.30 30.60 24.90 26.00 31.50 24.25 27.20
$27.80 34.50 21.55 21.40 30.60 25.40 22.80 31.40 25.25 26.90
It is known that the data of dinner expenses are normally distributed.
a. Determine the point estimate of the population mean dinner expenses.
b. Construct and interpret a 90% confidence interval estimate of the population mean dinner expenses.
c. Construct and interpret a 98% confidence interval estimate of the population proportion of marketing officers who spent at least $30.00 for dinner.
d. Assume that the sample standard deviation is an accurate estimate of the population standard deviation, how large a sample of dinner expense receipts would need to be taken in order to estimate the average expense to within 60 cents with 93.5% confidence?
Question 3.
Ben, a medical statistician wants to estimate the average weight loss for people who are on a new diet plan. In a preliminary study, he
Ryerson Automobile Insurance Company wants to estimate the mean time it takes for workers who are employed in downtown Toronto to get to work. A sample of 10 workers reveals the following number of minutes traveled. 38 33 21 45 34 57 46 62 25 40
It is known that the time it takes for all workers who are employed in downtown Toronto to get to work is normally distributed.
a. Determine the critical value(s) of a 91.5% confidence interval for the mean time it take for all workers who are employed in downtown Toronto to get to work
b. Construct a 91.5% confidence interval for the mean time it take for all workers who are employed in downtown Toronto to get to work. Interpret the result
Question 2.
In order to estimate the marketing officer’s dinner expenses when out of town on business, the office accountant took a random sample of dinner meal receipts and obtained the following results:
$23.80 36.50 28.75 21.30 30.60 24.90 26.00 31.50 24.25 27.20
$27.80 34.50 21.55 21.40 30.60 25.40 22.80 31.40 25.25 26.90
It is known that the data of dinner expenses are normally distributed.
a. Determine the point estimate of the population mean dinner expenses.
b. Construct and interpret a 90% confidence interval estimate of the population mean dinner expenses.
c. Construct and interpret a 98% confidence interval estimate of the population proportion of marketing officers who spent at least $30.00 for dinner.
d. Assume that the sample standard deviation is an accurate estimate of the population standard deviation, how large a sample of dinner expense receipts would need to be taken in order to estimate the average expense to within 60 cents with 93.5% confidence?
Question 3.
Ben, a medical statistician wants to estimate the average weight loss for people who are on a new diet plan. In a preliminary study, he