1. The level of lead in the blood was determined for a sample of 152 male and a sample of 86 female hazardous-waste workers, resulting in a mean + standard error of 5.5 + 0.3 for men and 3.8 10.2 for women. Let my be the difference between true average blood lead levels for male and female workers. (a) Is there substantial difference in the mean level of lead in the blood between these two groups? Conduct a hypothesis test at a significance level of 5%. Formulate the null and alternative hypothesis, propose a test statistic, describe the decision rule, and report your decision. (b) What is the power of the test if the difference pa is A' =0.5? What does this mean? (c) Construct a 95% confidence interval for the difference between true average blood levels for male and female workers. Using this interval alone, what do you conclude for the hypotheses in part (a)? (d) What assumptions do you make in the above calculations