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In: Statistics and Probability

A tudy was conducted to detemrine if a certain treatment has any effect on the amount of metal removed in a pickling operation.

A tudy was conducted to detemrine if a certain treatment has any effect on the amount of metal removed in a pickling operation. A random sample of 100 pieces were immersed in a bath for 24 hours without the treatment, yielding an average of 12.2 millimeters of metal removed and a sample standard deviation of 1.1 millimeters. A second sample of 200 pieces was exposed to the treatment, followed by the 24 hour immersion in the bath, resulting in an average removal of 9.1 millimeters of metal with a sample standard deviation of .9 millimeter. Compute a 98% confeidence interval estimate for the difference between the population means. Does the treatment appear to reduce theamount of metal removed.

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From the information

The 98% confidence interval for the difference between the two population means is 

                             

Thus , the 98 % confidence interval is ( 2.8104,3.3896 ) .

Since , the confidence interval does not contain 0 , and the interval is on positive side , the difference is said to be significant . Thus , the treatment appears to reduce the amount of metal removed .

SUN BUNRA answered 3 years ago
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