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.

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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

orchestra answered 3 years ago
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