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In: Statistics and Probability

A manufacturer bonds a plastic coating to a metal surface. A random sample of nine observations...

A manufacturer bonds a plastic coating to a metal surface. A random sample of nine observations on the thickness of this coating is taken from a week's output and the thickness (in millimeters) of these observations are shown below. Assuming normality, find a 90% confidence interval for the population variance.

19.1.

21.7

18.7

20.1

21.5

19.5

19.1

20.2

20.3

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