7.63. To compare the population mean annual incomes for Hispanics (^1) and for whiles (1x2) having jobs in construction, we construct a 95% confidence interval for fX2 — fx\.

(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 a = 0.05 level test of Hq: /x] = ix2 against Ha: /X] 1x2 rejects Hq.

(c) If the confidence interval is (-1000,3000), then it is plausible that fx\ = 1x2.

(d) If the confidence interval is (-1000,3000), then we arc 95% confident that the population mean annualincome forwhites is between

$1000 less and $3000 more than the population mean annual income for Hispanics.