Problem 8: Suppose the average zinc concentration taken from a sample of zinc measurements in 25 different locations of

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Problem 8 Suppose The Average Zinc Concentration Taken From A Sample Of Zinc Measurements In 25 Different Locations Of 1 (64.33 KiB) Viewed 26 times

Problem 8: Suppose the average zinc concentration taken from a sample of zinc measurements in 25 different locations of a river is found to be 3.0 ounces per gallon. Assume that the population is normally distributed with a standard deviation of 0.2. 1) Find the 95% confidence interval for the mean zinc concentration in the river. 2) How many samples would you need to make sure the estimation error of 95% confidence interval is less than 0.1? 3) If the population standard deviation is unknown and is estimated by the sample standard deviation s = 0.2. Find the 95% confidence interval for the mean zinc concentration in the river (Redo part 1)).