6.

Independent random samples from two regions in the same area gave the following chemical measurements (ppm). Assume the population distributions of the chemical are mound-shaped and symmetric for these two regions. Region I: X1; ] =12 438 1013 1127 737 491 840 306 402 1155 1075 500 340 Region II: x2; 12 =16 778 464 563 610 827 894 476 394 824 387 816 767 479 710 389 826 Let #1 be the population mean for X1 and #2 be the population mean for X2. Find a 90% confidence interval for #1 -#2. SHOW WORK REQUIRED: 1) State the general formula for the interval. 2) Show the plugging in of the appropriate values. 3) Find the interval using your calculator. State the keystrokes. 4) State the interval given in the calculator. 5) Interpret the result according to the authentic situation. O -119.75 to 248.25 O -114.49 to 242.99 O -253.50 to 125.00 O -248.25 to 119.75 O -125.00 to 253.50