Answer:
C.
Step-by-step explanation:
Given:
Add the two equations, we get
Therefore, the correct option is option C.
Suppose a regional computer center wants to evaluate the performance of its disk memory system.One measure of performance is the
average time between failures of its disk drive. To estimate this value, the center recorded the time between failures for a random sample of 45 disk-drive failures. The following sample statistics were computed: s . 215 hours # 1,762 hours Estimate the true mean time between failures with a 90% confidence interval. a) ) If the disk memory system is running properly, the true mean time between failures will exceed 1,700 hours. Based on the interval, in part a, what can you infer about the disk memory system?
1 answer:
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