Question

Increases in worker injuries and disability claims have prompted renewed interest in workplace design and regulation....

Increases in worker injuries and disability claims have prompted renewed interest in workplace design and regulation. As one particular aspect of this, employees required to do regular lifting should not have to handle unsafe loads. One study reported information regarding a random sample of 18 postal workers. The sample mean rating of acceptable load attained with a work-simulating test was found to be ? "=9.7 kg. Suppose we know that the standard deviation is ?=4.3 kg. Suppose that in a population of all male postal workers, the distribution of rating of acceptable load can be modeled using a normal distribution with mean ?.   
(e) Holding all else constant, how would the width of the confidence interval change if the standard deviation were 2.5 kg rather than 4.3 kg? Explain why.

(f) Suppose that you don’t know the population standard deviation but you do know that the sample standard deviation for the sample of 18 postal workers is 4.3 kg. Construct a 95% confidence interval for based on this information.

(g) Why is the confidence interval in (a) different from the confidence interval in (f)?

Homework Answers

Answer #1

since in part e the difference is positive therefore we can conclude that width of C.I is greater for sigma=4.3 as compared to sigma=2.5.

g) hii. you had not provide part a so i am not able to conclude exactly. but as i think in part one population standard deviation will be known. therefore confidence interval will be different because here in part f apply t statistic for critical value for unknown population variance by replacing sample variance but if population variance known than we apply z critical valie rather than t.

i hope you will understand well to answer. if you have any querry please ask by comment i will respond to you and please give your good rating to answer for providing the best quality answers in future. thanks....

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
A simple random sample of 100 postal employees is used to test if the average time...
A simple random sample of 100 postal employees is used to test if the average time postal employees have worked for the postal service has changed from the value of 7.5 years recorded 20 years ago. The sample mean was x¯ = 7 years with a standard deviation of s = 2 years. Assume the distribution of the time the employees have worked for the postal service is approximately Normal. The hypotheses being tested are H0 : µ = 7.5,...
Suppose we have the following paired observations of variables X and Y: X         Y 18        40...
Suppose we have the following paired observations of variables X and Y: X         Y 18        40 14        30 20        20 22        20             19        10             27        0 Calculate the values of the sample covariance and sample correlation between X and Y. Using this information, how would you characterize the relationship between X and Y?             (12 points) Suppose X follows a normal distribution with mean µ = 50 and standard deviation σ = 5. (10 points) What is the...
Total plasma volume is important in determining the required plasma component in blood replacement therapy for...
Total plasma volume is important in determining the required plasma component in blood replacement therapy for a person undergoing surgery. Plasma volume is influenced by the overall health and physical activity of an individual. Suppose that a random sample of 43 male firefighters are tested and that they have a plasma volume sample mean of x = 37.5 ml/kg (milliliters plasma per kilogram body weight). Assume that σ = 7.70 ml/kg for the distribution of blood plasma. (b) What conditions...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT