To compare the population mean annual incomes for Hispanics (1) and for whites (2) having jobs in

To compare the population mean annual incomes for Hispanics (μ1) and for whites (μ2) having jobs in construction, we construct a 95% confidence interval for

μ2 − μ1.

(a) If the confidence interval is (3000, 6000), then at this confidence level we conclude that the population mean income is higher for whites than for Hispanics.

(b) If the confidence interval is (−1000, 3000), then the corresponding α = 0.05-level test of H0: μ1 = μ2 against Ha: μ1 = μ2 rejects H0.

(c) If the confidence interval is (−1000, 3000), then it is plausible that μ1 = μ2.

(d) If the confidence interval is (−1000, 3000), then we are 95% confident that the population mean annual income for whites is between $1000 less and $3000 more than the population mean annual income for Hispanics.