Question

In: Statistics and Probability

If the population standard deviation of the lifetime of washing machines is estimated to be 900...

If the population standard deviation of the lifetime of washing machines is estimated to be 900 hours, how large a sample must be taken in order to be 96% confident that the margin of error will not exceed 100 hours?

Solutions

Expert Solution

The minimum sample is calculated as

N=344

Z is calculated using Z table shown below , normal curve

orchestra answered 1 year ago
Next > < Previous

Related Solutions

A dishwasher has a mean lifetime of 12 years with an estimated standard deviation of 1.25...
A dishwasher has a mean lifetime of 12 years with an estimated standard deviation of 1.25 years. Assume the lifetime of a dishwasher is normally distributed. Round the probabilities to four decimal places. It is possible with rounding for a probability to be 0.0000. a) State the random variable. rv X = the lifetime of a randomly selected dishwasher Correct b) Find the probability that a randomly selected dishwasher has a lifetime of 8.25 years or more. c) Find the...
The manufacture of a washing powder product used in automatic washing machines has estimated the following...
The manufacture of a washing powder product used in automatic washing machines has estimated the following demand equation for its product using data from 30 appliances stores around the country. Q= -350 - 2.0P + 1.2 Px + 5.0I + 6.0 A + 5.0U      (3.08) (0.60) (0.55)    (0.32) (0.80) (0.021) (SEC) The actual values for each of the independent variables are as follows. Assume the following information for the independent variables: Q = Quantity sold per month Price (P) of...
A company sells washing machines for $340 each. To produce a batch of n washing machines,...
A company sells washing machines for $340 each. To produce a batch of n washing machines, there is a cost of $249 per washing machine and a fixed or setup cost of $14,600 for the entire batch. Determine a function that gives the profit in terms of the number of washing machines produced. What is the least number of washing machines the company can sell in order to have a profit of $14,000?
Population 1 has an estimated mean of 50 and a sample standard deviation of 3 while...
Population 1 has an estimated mean of 50 and a sample standard deviation of 3 while population 2 has a sample mean of 48 and a sample standard deviation of 4. A sample of size 16 is taken for each population. Given that the sample sizes are small, we have to "pool the variances," operating on the assumption that the variances are equal. What is the value of pooled variance? What is the standard error of the difference in means,...
Population 1 has an estimated mean of 50 and a sample standard deviation of 3 while...
Population 1 has an estimated mean of 50 and a sample standard deviation of 3 while population 2 has a sample mean of 48 and a sample standard deviation of 4. A sample of size 16 is taken for each population. With the null being equality of means and the alternative being that the means are not equal, the conclusion as to the equality of means at the 90% level of confidence would be: A. Accept the null of no...
Population 1 has an estimated mean of 50 and a sample standard deviation of 3 while...
Population 1 has an estimated mean of 50 and a sample standard deviation of 3 while population 2 has a sample mean of 48 and a sample standard deviation of 4. A sample of size 16 is taken for each population. With the null being equality of means and the alternative being that the means are not equal, the conclusion as to the equality of means at the 90% level of confidence would be: A. Accept the null of no...
If the estimated lifetime benefit of a system is $870,000 and the estimated lifetime cost of...
If the estimated lifetime benefit of a system is $870,000 and the estimated lifetime cost of the system is $550,000. What is the estimated lifetime Return On Investment (ROI)? (First, state the formula). What is the annual percentage of the ROI if the estimated cost/benefit is for 4 years duration?     c.      What is the real annual cash value of the system?
QUESTION 2 Now suppose Joyce doesn't have population standard deviation (perhaps because these are new machines);...
QUESTION 2 Now suppose Joyce doesn't have population standard deviation (perhaps because these are new machines); she only has her sample standard deviation which is 12. Using the same information, (500 grams average, sample mean of 495, sample size of 24), what are the results of Joyce's analysis? (Check all that apply.) You will need to use one of the tables available on Blackboard (knowing which one is part of the question). Fail to reject the null hypothesis. Reject the...
The average lifetime of a light bulb is 3000 hours with a standard deviation of 696...
The average lifetime of a light bulb is 3000 hours with a standard deviation of 696 hours. A simple random sample of 36 bulbs is taken. What is the probability that the average life in the sample will be greater than 3219.24? Note: respond in decimal form, for example, if your solution is 87.1234%, you should enter in 0.871234.
The average lifetime of a light bulb is 2850 hours with a standard deviation of 400....
The average lifetime of a light bulb is 2850 hours with a standard deviation of 400. A simple random sample of 30 bulbs is taken. What is the probability that the average life in the sample will be between 2600 and 2700 hours?
ADVERTISEMENT
Subjects
ADVERTISEMENT
Latest Questions
ADVERTISEMENT