Question

In: Statistics and Probability

. Suppose a PC manufacturer wants to evaluate the performance of its hard disk memory system....

. Suppose a PC manufacturer wants to evaluate the performance of its hard disk memory system. One measure of performance is the average time between failures of the disk drive. To estimate this value, a quality control engineer recorded the time between failures for a random sample of 49 disk-drive failures. A summary of the sample statistics was that x-bar = 5,790.36 hours and with sample standard deviation s = 224 hours. Estimate the true mean time between failures with a 90% CI.

Solutions

Expert Solution

We have given that,          
          
Sample mean =   5790.36   hours
Sample standard deviation =224 hours
Sample size =   49  
Level of significance=1-0.90=   0.1  
Degree of freedom =48  
          
t critical value is (by using t table)=   1.6772  
          
Confidence interval formula is



=(5736.69,5844.03)          
          
          
          
Lower confidence limit=   5736.69 hours
          
Upper confidence limit=   5844.03 hours


Related Solutions

Suppose that a system uses DMA for data transfer from disk controller to main memory. Further...
Suppose that a system uses DMA for data transfer from disk controller to main memory. Further assume that it takes t1 nsec on average to acquire the bus and t2 nsec to transfer one word over the bus (t1 >> t2). After the CPU has programmed the DMA controller, how long will it take to transfer 1000 words from the disk controller to main memory, if (a) word-at-a-time mode is used? (b) burst mode is used? Assume that commanding the...
Should an operating system process scheduler treat a process that makes extensive use of a hard-disk...
Should an operating system process scheduler treat a process that makes extensive use of a hard-disk storage device differently from one that makes extensive use of a solid-state storage device? Give your reasons.
A computer memory manufacturer specifies that its memory chip stores data incorrectly an average of 6.3...
A computer memory manufacturer specifies that its memory chip stores data incorrectly an average of 6.3 out of 10 million cycles with a standard deviation of 0.48. A batch of 30 chips your company ordered stores data incorrectly an average of 6.9 times per 10 million cycles. a. Does it seem reasonable that your 30 chips are a random sample from a population with the specifications given by the computer memory manufacturer? Use a = 0.052 tail. b. What is...
A car manufacturer wants to compare the performance of engines using ethanol mix with that of...
A car manufacturer wants to compare the performance of engines using ethanol mix with that of those using pure gasoline. They start by randomly choosing 200 cars, and divide that sample into two equally sized groups. The sample average performance for 100 cars using ethanol is 76.5 on a 0 to 100 scale, and the sample standard deviation is 38. For the other sample of cars, they test using pure gasoline and the average performance is 88.1 and the sample...
A car manufacturer wants to compare the performance of engines using ethanol mix with that of...
A car manufacturer wants to compare the performance of engines using ethanol mix with that of those using pure gasoline. They start by randomly choosing 200 cars, and divide that sample into two equally sized groups. The sample average performance for 100 cars using ethanol is 76.5 on a 0 to 100 scale, and the sample standard deviation is 38. For the other sample of cars, they test using pure gasoline and the average performance is 88.1 and the sample...
Evaluate the requirements of an effective performance appraisal system. What are the pros and cons?
Evaluate the requirements of an effective performance appraisal system. What are the pros and cons?
Suppose that the WTAMU post-office wants to develop a new system that will give its user...
Suppose that the WTAMU post-office wants to develop a new system that will give its user more on-line experience. The post office plans to serve WTAMU students identifying through their ID, or with help from the university information. The new system will facilitate as like the IT service center, a student/faculty/staff will be allowed to create tokens to send/receive their mails, and the post office workers will collect the mail from the service location. You have been put in charge...
Evaluate the performance of smart antennas compared to traditional antennas for a given communication system. For...
Evaluate the performance of smart antennas compared to traditional antennas for a given communication system. For a given communication system design, what factors will you consider if choosing to deploy smart antennas? Describe at least two types of smart antennas and their working.
Die Hard Company is a pesticide manufacturer. Its sales declined greatly this year due to the...
Die Hard Company is a pesticide manufacturer. Its sales declined greatly this year due to the passage of legislation outlawing the sale of several of Die Hard's chemical pesticides. In the coming year, Die Hard will have environmentally safe and competitive chemicals to replace these discontinued products. Sales in the next year are expected to greatly exceed any prior year's. The decline in sales and profits appears to be a one-year aberration. But even so, the company president fears a...
Aztec, a manufacturer of hard board and fiber cement sidings and panels, purchased equipment for its...
Aztec, a manufacturer of hard board and fiber cement sidings and panels, purchased equipment for its new product line 9 years ago at a cost of $43,000. The asset has a market value of $17,700, if it were sold now. The current asset is expected to provide adequate services for another 3 years, given that the annual maintenance costs of $7250 is provided. It is estimated that, if the current asset is continued in service, its final market value will...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT