Question 1162463: To estimate the average time it takes to assemble a certain computer component the industrial engineer at an electronics firm timed 49 technicians in the performance of this task, getting a mean of 12.00 minutes and a standard deviation of 1.90 minute. (i) What can we say with 95% confidence about the maximum error if X = 12.00 is used as a point estimate of the actual average time required to do the job? (ii) Use the given data to construct a 99% confidence interval for the true average time it takes to assemble the computer components.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! this is a 95% t-interval with x bar 12, s=1.9 min, and n=49
t 0.975, df=48=2.01
half-interval is 2.01*s/sqrt(n)=2.01*1.90/7=0.545
the 95% CI is (11.45, 12.55) min
for 99%, t=2.68
half-interval is 2.68*1.9/7=0.727 or 0.73
99% interval is (11.27, 12.73) min
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