- A B 79 98 80 04 80 02 80 04 80 03 80 03 80 04 79 97 80 05 80 03 80 02 80 00 80 02 80 02 79 94 79 98 79 97 79 97 80 03 79 1 (40.65 KiB) Viewed 104 times
(b) Assuming that the population variances are equal, is
there evidence of a difference in calories
per gram of mass between the two methods at a 0.10 significance
level?
(c) Obtain the confidence interval of the average
difference between the two methods at a 90%
confidence level, and make a statistical decision based on the
interval.
(d) Compare the results from (b) and (c)
2. The data set (Concrete.xlsx) contains the compressive
strength, in thousands of pounds per
square inch (psi), of 40 samples of concrete taken two and seven
days after pouring.
- A B 79 98 80 04 80 02 80 04 80 03 80 03 80 04 79 97 80 05 80 03 80 02 80 00 80 02 80 02 79 94 79 98 79 97 79 97 80 03 79 2 (108.29 KiB) Viewed 104 times
difference in the mean strengths at
two days and at seven days?
(b) Find the p-value of the test in (a) and interpret its
meaning.
(c) At the 0.01 level of significance, is there evidence that the
mean strength is lower at two days
than at seven days?
(d) Find the p-value of the test in (c) and interpret its
meaning.
A B 79.98 80.04 80.02 80.04 80.03 80.03 80.04 79.97 80.05 80.03 80.02 80.00 80.02 80.02 79.94 79.98 79.97 79.97 80.03 79.95 79.97
11 15 Sample Two Days Seven Days 1 2.830 3.505 2 3.295 3.430 3 2.710 3.670 4 2.855 3.355 5 2.980 3.985 6 3.065 3.630 7 3.765 4.570 8 3.265 3.700 9 3.170 3.660 10 2.895 3.250 2.630 2.850 12 2.830 3.340 13 2.935 3.630 14 3.115 3.675 2.985 3.475 16 3.135 3.605 17 2.750 3.250 18 3.205 3.540 19 3.000 4.005 20 3.035 3.595 21 1.635 2.275 22 1.765 3.415 23 2.045 3.225 24 2.670 3.790 25 1.355 4.575 26 1.425 4.070 27 3.875 5.100 28 3.020 3.205 29 2.290 4.260 30 2.495 3.405 31 2.980 3.925 32 2.300 4.215 33 3.570 4.705 34 1.275 4.070 35 2.270 3.910 36 2.895 2.915 37 2.845 4.530 2.205 2.280 39 3.590 3.915 40 2.675 3.655 38