In a random sample of 18 people, the mean commute time to work was 34.3 minutes and the standard deviation was 7.3 minutes. Assume the population is normally distributed and use a t-distribution to construct a 99% confidence interval for the population mean p. What is the margin of error of u? Interpret the results. The confidence interval for the population mean u is ID (Round to one decimal place as needed.) The margin of error of u is (Round to one decimal place as needed.) Interpret the results. ess O A. With 99% confidence, it can be said that the population mean commute time is between the bounds of the confidence interval. O B. It can be said that 99% of people have a commute time between the bounds of the confidence interval bral O C. If a large sample of people are taken approximately 99% of them will have commute times between the bounds of the confidence interval. O D. With 99% confidence, it can be said that the commute time is between the bounds of the confidence interval. tions

The distribution of study times for first-year students follow a Normal distribution with a standard deviation σ = 48 minutes. Suppose a sample of 344 students found that the mean study time for these students was x¯= 170 minutes per week. Use this to find a 94.38% confidence interval to estimate the mean study time for all students. We are 94.38% confident that the mean study time for first-year students is between the following ( answer) minutes and  ( answer) minutes. The answer needs to be the mean study time for first-year students is between what amount of minutes and the following minutes.

Find the 95% confidence interval for the variance and standard deviation for the time it takes a state police inspector to check a truck for safety if a sample of 21 trucks has a standard deviation of 5.2 minutes. Assume the variable is normally distributed.

The average gold content from an ore sample in 36 different locations is found to be 2.6 grams per ton. a. Find the 95% and 99% confidence intervals for the mean gold content in that area. Assume that the population variance is 0.09.

From a sample of 37 graduate students, the mean number of months of work experience prior to entering an MBA program was 36.63. The national standard deviation is known to be 19 months. What is a 90% confidence interval for the population mean? A 90% confidence interval for the population mean is 10 (Use ascending order. Round to two decimal places as needed.) ...

In a random sample of 17 people, the mean commute time to work was 30.2 minutes and the standard deviation was 7.1 minutes. Assume the population is normally distributed and use a t- distribution to construct a 95% confidence interval for the population mean y. What is the margin of error of y? Interpret the results.

Work Time Lost due to Accidents At a large company, the Director of Research found that the average work time lost by employees due to accidents was 102 hours per year. She used a random sample of 21 employees. The standard deviation of the sample was 5.4 hours. Estimate the population mean for the number of hours lost due to accidents for the company, using a 99% confidence interval. Assume the variable is normally distributed. Use a graphing calculator and round the answers to the nearest whole number.

In a random sample of twelve people, the mean driving distance to work was 21.3 miles and the standard deviation was 7.3 miles. Assume the population is normally distributed and use the t-distribution to find the margin of error and construct a 99% confidence interval for the population mean μ. Interpret the results. Identify the margin of error. (Rol square miles miles per hour miles s needed.)

Overweight Men For a random sample of 70 overweight men, the mean of the number of pounds that they were overweight was 29. The standard deviation of the population is 4.3 pounds. Find the 90% confidence interval of the mean of these pounds. Round intermediate answers to at least three decimal places.

A ecologist wishes to estimate the mean lifespan for a specific species of bird. Assume that bird lifespan is normally distributed and that each bird's lifespan is independent of all others. The researcher analyzes a random sample of n=7 deceased birds to find out how long they lived for. It is found that the mean lifespan in the sample is y= 5 4 years with standard deviation s=13 years. Choose the correct formula for a 95% confidence interval for the true mean lifespan. X± to.975,n O xt to.975,n-1 n-1 O none of these X+ Z0.975 O x+ to.975,n-1' O xt to.975,n-15