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Water Trace metals found in wells affect the taste of drinking water, and high
Chapter 8, Problem 72(choose chapter or problem)
Water Trace metals found in wells affect the taste of drinking water, and high concentrations can pose a health risk. Researchers measured the concentration of zinc (in milligrams/liter) near the top and the bottom of 10 randomly selected wells in a large region. The data are provided in the table below.30 (a) Construct and interpret a 95% confidence interval for the mean difference m in the zinc concentrations from these two locations in the wells. (b) Does your interval in part (a) give convincing evidence of a difference in zinc concentrations at the top and bottom of wells in the region? Justify your answer. Well: 1 2 3 4 5 6 7 8 9 10 Bottom: 0.430 0.266 0.567 0.531 0.707 0.716 0.651 0.589 0.469 0.723 Top: 0.415 0.238 0.390 0.410 0.605 0.609 0.632 0.523 0.411 0.612 Difference: 0.015 0.028 0.177 0.121 0.102 0.107 0.019 0.066 0.058 0.111
Questions & Answers
QUESTION:
Water Trace metals found in wells affect the taste of drinking water, and high concentrations can pose a health risk. Researchers measured the concentration of zinc (in milligrams/liter) near the top and the bottom of 10 randomly selected wells in a large region. The data are provided in the table below.30 (a) Construct and interpret a 95% confidence interval for the mean difference m in the zinc concentrations from these two locations in the wells. (b) Does your interval in part (a) give convincing evidence of a difference in zinc concentrations at the top and bottom of wells in the region? Justify your answer. Well: 1 2 3 4 5 6 7 8 9 10 Bottom: 0.430 0.266 0.567 0.531 0.707 0.716 0.651 0.589 0.469 0.723 Top: 0.415 0.238 0.390 0.410 0.605 0.609 0.632 0.523 0.411 0.612 Difference: 0.015 0.028 0.177 0.121 0.102 0.107 0.019 0.066 0.058 0.111
ANSWER:Step 1 of 8
(a)
Determine the difference between bottom and top of each pair of data.
Sample1 |
Sample 2 |
Difference D |
0.43 |
0.415 |
0.015 |
0.266 |
0.238 |
0.028 |
0.567 |
0.39 |
0.177 |
0.531 |
0.41 |
0.121 |
0.707 |
0.605 |
0.102 |
0.716 |
0.609 |
0.107 |
0.651 |
0.632 |
0.019 |
0.589 |
0.523 |
0.066 |
0.723 |
0.612 |
0.111 |
mean |
0.0804 |
|
sd |
0.0523 |