Determining 90 percent confidence interval

Assignment Help Operation Management

Reference no: EM13100709

The Ajax Corporation would like to know the average age of its employees. The average age of a sample of 100 employees is 28 years with a standard deviation of 6.5 years.

a. What is the 90% confidence interval for the average age of all the employees? (Round this answer to the nearest whole number.)

b. How many employee records need to be checked to increase the confidence to 95% with the same interval (range)?

c. 32% of the sampled employees from the Ajax Corporation have been employed for at least 60 months. What is the 95% confidence interval for the proportion of employees that have average employment of at least 60 months?

d. How may employee records need to be checked to for the company to be 90% confident that its estimated proportion was within 5%?

Reference no: EM13100709

Questions Cloud

Find the ratio of the wave speeds : Two steel guitar strings have the same length. String A has a diameter of 0.59 mm and is under 450.0 N of tension. String B has a diameter of 1.2 mm and is under a tension of 800.0 N. Find the ratio of the wave speeds, va/vb, in these two strings.

Explain issues in multicultural psychology : Explain the influence that these issues will have on society. Describe how these issues will influence the interaction among culturally diverse groups.

Question-poisson distribution : Do you think the Poisson distribution, which assumes independent arrivals, is a good estimation of arrival rates in the following queuing systems? Defend your position in each case.

Does the change in speed of the downward-moving rock : Does the change in speed of the downward-moving rock agree with the magnitude of the speed change of the rock moving upward between the same elevations? Explain physically why it does or does not agree.

Determining 90 percent confidence interval : The Ajax Corporation would like to know the average age of its employees. The average age of a sample of 100 employees is 28 years with a standard deviation of 6.5 years.

Rejecting the officials claim : A state transportation official claims that the mean waiting time at exit booths from a toll road near the capitol is no more than .40 minutes. for a sample of 35 motorists exiting the toll road, it was found that the mean waiting time was .46 min..

Normal probability-average cost of renting : The average cost of a renting a compact size car in a major metropolitan area is R51.74 with a standard deviation of 7.48. Assume a normal distribution.

Find the number of moles of gas : A rigid tank contains 1.40 moles of an ideal gas. Determine the number of moles of gas that must be withdrawn from the tank to lower the pressure of the gas from 27.2 atm to 5.90 atm. Assume the volume of the tank and the temperature of the gas re..

Estimate the proportion of prospective customers : The Luxor Computer Company plans to introduce a pyramid-shaped desktop computer. The company is interested in the proportion of prospective customers who find the unusual shape a positive selling point.

User Account

All Pages