Truckloads of waste contaminated with cadmium may either be sentto a sanitary landfill or a hazardous waste landfill. The levels ofcadmium vary daily so each morning a sample of truckloads must betested to determine which landfill to use. If the mean level ofcadmium exceeds the allowable amount of 1 milligram per liter for asanitary landfill then the trucks must be sent further to thehazardous landfill. Of course, driving a further distance requiresmore expense for the company. You are in charge of testing anddetermining which landfill to use for dumping for today.

You will use a 5% level of significance for your hypothesistest.

1. State the null and alternative hypotheses, and identify whichrepresents the claim. Why?

2. Determine the type of test that you should use: left-tailed,right-tailed, or two-tailed. Explain your reasoning.

3. What sampling technique would you use to determine yoursample of truckloads that will be tested this morning? Should asmall sample or a large sample be used? Does it really matter?

4. What decision concerning your null hypothesis would result ina Type I error? What is the interpretation and the implication ofthis error? What about a Type II error? Obviously, you want tominimize the risk of both types of error when decision making.Which of these errors is more serious in this situation?

5. Suppose that the null hypothesis is rejected when you performyour hypothesis test. Assuming that a correct decision was made,what do you believe regarding the mean level of cadmium on today'struckloads? Give a complete interpretation.