Persons submitting computing jobs to a computer center usually are required to estimate

Chapter 12, Problem 12.34

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Persons submitting computing jobs to a computer center usually are required to estimate the amount of computer time required to complete the job. This time is measured in CPUs, the amount of time that a job will occupy a portion of the computers central processing units memory. A computer center decided to perform a comparison of the estimated versus actual CPU times for a particular customer. The corresponding times were available for 11 jobs. The sample data are given in the accompanying table.Job Number CPU Time (minutes) 1 2 3 4 5 6 7 8 9 10 11 Estimated .50 1.40 .95 .45 .75 1.20 1.60 2.6 1.30 .85 .60 Actual .46 1.52 .99 .53 .71 1.31 1.49 2.9 1.41 .83 .74 a Why would you expect that the observations within each of these pairs of data to be correlated? b Do the data provide sufficient evidence to indicate that, on the average, the customer tends to underestimate the CPU time required for computing jobs? Test using = .10. c Find the observed significance level for the test and interpret its value. d Find a 90% confidence interval for the difference in mean estimated CPU time versus mean actual CPU time.