(Solution Download) The precision of equipment and instruments is measured by the

The precision of equipment and instruments is measured by the variability of their operation under repeated conditions. The output from an automatic lathe producing the diameter (in millimeters) of a part gave the following readings for a random sample of size 10:

(a) Find a 90% confidence interval for the variance of the diameters.
(b) Find a 90% confidence interval for the standard deviation of the diameters.
(c) Test the null hypothesis that variance of the diameters does not exceed 0.05 mm. Use a significance level of 0.10.
(d) Does the mean setting for the machine need adjustment? Is it significantly different from 9.5 mm? Test at a significance level of 0.10.

 

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