The data in the accompanying table represent the compressive strength, in thousands of pounds per square inch (psi), of 20 samples of concrete taken two and seven days after pouring. Complete parts (a) through (c) below.
At the .01 level of significance, is there evidence that the mean strength is lower at two days than at seven days?
Sample |
Two days |
Seven days |
1 |
3.115 |
3.675 |
2 |
3.17 |
3.66 |
3 |
3.765 |
4.57 |
4 |
2.845 |
4.53 |
5 |
3.035 |
3.595 |
6 |
3.205 |
3.59 |
7 |
3.315 |
3.685 |
8 |
3.065 |
3.63 |
9 |
2.98 |
3.985 |
10 |
3.8 |
4.07 |
11 |
2.83 |
3.34 |
12 |
2.75 |
3.25 |
13 |
2.495 |
3.23 |
14 |
2.27 |
3.91 |
15 |
3.135 |
3.605 |
16 |
3.08 |
3.14 |
17 |
2.005 |
2.69 |
18 |
3.425 |
4.03 |
19 |
3.265 |
3.7 |
20 |
2.985 |
3.475 |
Determine the test statistic?
What the critical values?
Find the P-value?
We need at least 10 more requests to produce the answer.
0 / 10 have requested this problem solution
The more requests, the faster the answer.
The data in the accompanying table represent the compressive strength, in thousands of pounds per square...
The data in the accompanying table represent the compressive strength, in thousands of pounds per square inch (psi), of 20 samples of concrete taken two and seven days after pouring. At the 0.05 level of significance, is there evidence that the mean strength is lower at two days than at seven days? Click the icon to view the data table. HAH70 C. Ho Hd 20 HA Hd < 0 HAHd > 0 O D. Ho 070 HAM = 0 Find...