In examining the credit accounts of a department store, an auditor would like to estimate the tru...
help! In examining the credit accounts of a department store, an auditor would like to estimate the true mean account error (book value – audited value). To do so, the auditor selected a random sample of 50 accounts and found the mean account error to be $60 with a standard deviation of $30. a.Construct a 95% confidence interval for the population mean account error. What conclusion can be made from this confidence interval? b.How large a sample is actually needed...
A) A certain region would like to estimate the proportion of voters who intend to participate in upcoming elections. A pilot sample of 25 voters found that 17 of them intended to vote in the election. Determine the additional number of voters that need to be sampled to construct a 95% interval with a margin of error equal to 0.06 to estimate the proportion. The region should sample ____ additional voters. B) Determine the sample size needed to construct a...
5. The servicing time at the drive-through lane of a fast food restaurant follows an exponential distribution. The average servicing time is 2 minutes. (4 points) YORKVILLE BUSI 1013 statistics for Business What is the probability that it takes more than 2.5 minutes to service a customer at the drive-through lane? b. a. What percent of customers at the drive-through lane will take between 1 to 3 minutes to service? Part B 1. A simple random sample of 50 customers...
4. A simple random sample of 100 customers is selected from an account receivable portfolio and the sample mean account balance is $3000. The population standard deviation σ is known to be $300. ( 8 marks) a. Construct a 90% confidence interval for the mean account balance of the population. b. What is the margin of error for estimating the mean account balance at the 90% confidence level? c. Construct a 90% confidence interval for the mean account balance of...
QUESTION 10 A large regional department store is evaluating the effectiveness of its credit card program, which costs it approximately $1m per year to administer. The store believes that for the credit card program to be worthwhile, the administrative costs should be no more than 10% of the total of the average annual account balances. Rather than reviewing each of the 15,000 individual accounts, the store's analysts randomly selected a sample of 500 average annual balances from the frame. The...
Suppose you construct a 95% confidence interval estimate of the true population mean by conducting a random sample of size n=100. Your sample mean x (with a bar over it) = 80.5 and your calculated maximum error of the estimate is E = 3.5. What does this suggest? Circle answer. a. in 5% of all samples of this size, the mean is more than 84, b. in 95% of all samples of this size, the mean is at least 77,...
An auditor for a hardware store chain wished to compare the efficiency of two different auditing techniques. To do this he selected a sample of nine store accounts and applied auditing techniques A and B to each of the nine accounts selected. The number of errors found in each of techniques A and B is listed in the table below; ors in A Errors in B 45 48 46 48 52 50 49 40 45 31 37 39 37 54...
1. A prison official wants to estimate the proportion of cases of recidivism. Examining the records of 238 convicts, the official determines that there are 92 cases of recidivism. Find the lower limit of the 90% confidence interval estimate for the population proportion of cases of recidivism. (Round to 3 decimal places.) 2. A prison official wants to estimate the proportion of cases of recidivism. Examining the records of 157 convicts, the official determines that there are 47 cases of...
5. A manufacturing company produces electric insulators. To test the strength of the insulators, you apply a force to an insulator until it breaks. You measure the force by observing! how many pounds are required to break the insulator. You collect the force data for a random sample of 30 insulators selected for this experiment. The data is in the Excel file for this assignment in the tab Force. a. Construct a 95% confidence interval estimate for the population mean...
answer is not 194 A restuarant would like to estimate the proportion of tips that exceed 18% of its dinner bills. Without any knowledge of the population proportion, determine the sample size needed to construct a 97% confidence interval with a margin of error of no more than 6% to estimate the proportion. A restuarant would like to estimate the proportion of tips that exceed 18% of its dinner bills. Without any knowledge of the population proportion, determine the sample...