Question

Question 1 of 10 (1 point) | Attempt 6 of Unlimited View question in a popup 11.1 Section Exercise 13 (critical value, table) Contaminated water: The concentration of benzene was measured in units of milligrams per liter for a simple random sample of five specimens of untreated wastewater produced at a gas field. The sample mean was 8.3 with a sample standard deviation of 1.1. Seven specimens of treated wastewater had an average benzene concentration of 3.7 with a standard deviation of 3.3. It is reasonable to assume that both samples come from populations that are approximately normal. Can you conclude that the mean benzene concentration is less in treated water than in untreated water? Let u, denote the mean benzene concentration in untreated wastewater. Use the a=0.01 level and the critical value method with the table. E Part 1 of 6 State the appropriate null and alternate hypotheses. olo H: 4 = 42 H: ">" This is a right-tailed V test.

Answer 1

critical value at da 0.01 is, tn-1;& = tio, o.ol = 2.764 Decision : Reject the null hypothes is, I tol=2.96 > 1 tio; o.0, 1 = 2-764 since Conclusion: We Conclude that the meam benzene concentration is less in treated water than in untreated water.