Shake Shack at the mall is a popular destination with long wait times. Suppose we wish...
Shake Shack at the mall is a popular destination with long wait times. Suppose we wish to estimate the wait time for customers at peak dinner time. Assume a previous random sample of size 30 was taken and the sample mean was found to be 14.82 minutes with a sample standard deviation of 4.13 minutes. How large a sample should they take to estimate the true mean wait time to be within 1.2 minutes at the 95% confidence interval?
Homework Answers
Given that, standard deviation = 4.13 minutes
margin of error ( E ) = 1.2 minutes
A 95% confidence level has significance level of 0.05 and
critical value is 
We want to find, the sample size ( n ),
Therefore, required sample size is 46
Note: if we used t-critical value, which is 2.045 then sample size would be 50
Add Answer to:
Shake Shack at the mall is a popular destination with long wait
times. Suppose we wish...
Suppose that the wait times for patients in an emergency room are normally distributed with an...
Suppose that the wait times for patients in an emergency room are normally distributed with an unknown mean and standard deviation. A random sample of 18 patients is taken and gives a sample mean of 25 minutes and a sample standard deviation of 2 minutes. As found above, the EBM, margin of error, for a 95% confidence interval estimate for the population mean using the Student's t-distribution is 0.99. Find a 95% confidence interval estimate for the population mean using...
A popular Italian eatery has had a dispute among the wait staff regarding the amount of tips waiters receive on the lun...
A popular Italian eatery has had a dispute among the wait staff regarding the amount of tips waiters receive on the lunch shift and on the dinner shift. Before making any adjustments in schedules or other policies, the restaurant manager wants to estimate the difference in the average tips earned by waiters on the lunch schedule and on the dinner schedule. To do this, she randomly selected 60 tip reports for lunch servers over the past year and 40 tip...
The Department of Motor Vehicles is concerned about the length of time customers wait in line...
The Department of Motor Vehicles is concerned about the length of time customers wait in line at the Sacramento office. The satisfaction surveys indicate the wait time may be well above the statewide average of 11.30 minutes for all DMV offices. DMV wants to closely monitor the wait time. To start, a sample of 250 customers’ wait time was drawn to develop a baseline performance target for the performance tracking. The average wait time of the sample is 11.90 minutes,...
Suppose that pizza delivery times are normally distributed with a population standard deviation of 6 minutes....
Suppose that pizza delivery times are normally distributed with a population standard deviation of 6 minutes. A random sample of 50 pizza delivery restaurants is taken and has a sample mean delivery time of 36 minutes. Construct a 90% confidence interval for the population mean delivery time. What is the sample mean? 6 1.87 36 1.64 What is the sample size? 8.33 90 50 36 What is the population standard deviation? 0.85 50 36 6 What is the confidence level?...
we wish to estimate μ, the mean length of the fish in our pond. we take...
we wish to estimate μ, the mean length of the fish in our pond. we take a random sample of 65 fish and measure their lengths. for this sample, we find an average length of 4.53 cm, and a standard deviation of 0.8cm. i) using our observations as a pilot study, determine the sample size needed to estimate the mean μ within 0.1cm with 95% confidence. ii) find the upper confidence interval for μ
A market researcher collects a simple random sample o customers from a population o over a...
A market researcher collects a simple random sample o customers from a population o over a million customers that use a home improvement website. After analyzing the sample, she states that she has 95% confidence that the mean time customers spent on that website per day is between 17 and 52 minutes. Suppose that the population mean time customers spent on that website is 49 minutes a day. Does this value of the population mean help to show that the...
Consider a population having a standard deviation equal to 9.96. We wish to estimate the mean...
Consider a population having a standard deviation equal to 9.96. We wish to estimate the mean of this population. (a) How large a random sample is needed to construct a 95% confidence interval for the mean of this population with a margin of error equal to 1? (Round your answer to the next whole number.) The random sample is units. (b) Suppose that we now take a random sample of the size we have determined in part a. If we...
Suppose a retailer claims that the average wait time for a customer on its support line...
Suppose a retailer claims that the average wait time for a customer on its support line is 170 seconds. A random sample of 54 customers had an average wait time of 160 seconds. Assume the population standard deviation for wait time is 50 seconds. Using a 95% confidence interval, does this sample support the retailer's claim? Using a 35% confidence interval, does this sample support the retailer's claim? Select the correct choice below, and fill in the answer boxes to...
A random sample of 49 cherry shop customers was taken. The sample’s mean amount of time...
A random sample of 49 cherry shop customers was taken. The sample’s mean amount of time these cus-tomers stayed in the shop was 30 minutes with a sample standard deviation of 10 minutes. Develop a 95% confidence interval estimate for the mean of the population by answering this a) What is the margin of error? b) What is the confidence interval? c) Interpret your answer
We wish to give a 95% confidence interval for the difference in average times it takes...
We wish to give a 95% confidence interval for the difference in average times it takes workers to complete a routine task before and after taking a training class. Below we give the results for two independent samples in which the times (in minutes) were recorded for the task. Before Training After training Sample Size 48 44 Sample Average 9.5 8.6 Sample SD 2.1 1.9 In what follows let µ1 denote the population average time of completion without the training...
A popular Italian eatery has had a dispute among the wait staff regarding the amount of tips waiters receive on the lunch shift and on the dinner shift. Before making any adjustments in schedules or other policies, the restaurant manager wants to estimate the difference in the average tips earned by waiters on the lunch schedule and on the dinner schedule. To do this, she randomly selected 60 tip reports for lunch servers over the past year and 40 tip...
A market researcher collects a simple random sample o customers from a population o over a million customers that use a home improvement website. After analyzing the sample, she states that she has 95% confidence that the mean time customers spent on that website per day is between 17 and 52 minutes. Suppose that the population mean time customers spent on that website is 49 minutes a day. Does this value of the population mean help to show that the...
Consider a population having a standard deviation equal to 9.96. We wish to estimate the mean of this population. (a) How large a random sample is needed to construct a 95% confidence interval for the mean of this population with a margin of error equal to 1? (Round your answer to the next whole number.) The random sample is units. (b) Suppose that we now take a random sample of the size we have determined in part a. If we...
Suppose a retailer claims that the average wait time for a customer on its support line is 170 seconds. A random sample of 54 customers had an average wait time of 160 seconds. Assume the population standard deviation for wait time is 50 seconds. Using a 95% confidence interval, does this sample support the retailer's claim? Using a 35% confidence interval, does this sample support the retailer's claim? Select the correct choice below, and fill in the answer boxes to...
Most questions answered within 3 hours.
-
Are the following two functions overloaded?
int xyz(int x, int y = 100000);
int xyz(int x,...
asked 44 seconds ago -
An interest rate swap has three years of remaining life.
Payments are exchanged annually. Interest at...
asked 7 minutes ago -
Ensign Johnson is domiciled in Georgia. His wife is domiciled in
New York and moved to...
asked 4 minutes ago -
there are many issues that can be addressed when performing a
RCA. Assuming that there is...
asked 6 minutes ago -
ata pertaining to the postretirement health care benefit plan of
Danielson Delivery Service include the following...
asked 8 minutes ago -
Getting along with the members of your team requires good ____
skills.
a.
authoritative
b.
problem...
asked 15 minutes ago -
During June, Propene Company produced 20,000 chainsaw blades.
The standard quantity of material allowed per unit...
asked 21 minutes ago -
Draw the molecular orbital energy level diagrams and write the
electron configurations of (a) Be2, (b)...
asked 22 minutes ago -
We put a mixture of helium, oxygen and nitrogen gases in a
closed container at 25...
asked 32 minutes ago -
You measure 22 dogs' weights, and find they have a mean weight
of 64 ounces. Assume...
asked 39 minutes ago -
Complete and balance the following methesis reaction in aqueous
solution.
Instructions
• Use proper element capitalization....
asked 51 minutes ago -
Green Tree Corporation is expecting to receive $0.5 million at
the end of Year 1, $0.25...
asked 1 hour ago