
Concept explainers
Online testing: Do you prefer taking tests on paper or online? A college instructor gave identical tests to two randomly sampled groups of 35 students. One group took the test on paper and the other took it online. Following are the test scores.
- Construct a 95% confidence interval for the difference in
mean scores between paper and online tests. - The instructor claims that the mean scores are the same for both the paper and the online versions of the test. Does the confidence Interval contradict this claim?
a.

To find: The
Answer to Problem 25E
The
Explanation of Solution
Given information:
The data is,
Paper | ||||||
79 | 75 | 49 | 78 | 73 | 81 | 70 |
63 | 79 | 65 | 60 | 74 | 64 | 64 |
74 | 69 | 57 | 65 | 61 | 58 | 92 |
71 | 69 | 66 | 71 | 68 | 67 | 81 |
78 | 80 | 76 | 67 | 49 | 56 | 45 |
Online | ||||||
79 | 75 | 71 | 81 | 56 | 72 | 49 |
75 | 63 | 81 | 74 | 72 | 71 | 73 |
83 | 59 | 78 | 65 | 53 | 47 | 63 |
82 | 81 | 76 | 65 | 82 | 78 | 76 |
65 | 72 | 85 | 84 | 81 | so | 79 |
Concept used:
Minitab is used.
Calculation:
The steps for the confidence interval are,
Import the data, select start and choose the basic statistics option then select the 2 sample t and enter summarized data.
Click option button choose confidence level, test difference and alternative hypothesis and then click ok.
The data is shown below.
Figure-1
Therefore, the
b.

To find: Whether the confident interval contradict the claim.
Answer to Problem 25E
The confident interval does not contradict the claim
Explanation of Solution
Given information:
The data is,
Paper | ||||||
79 | 75 | 49 | 78 | 73 | 81 | 70 |
63 | 79 | 65 | 60 | 74 | 64 | 64 |
74 | 69 | 57 | 65 | 61 | 58 | 92 |
71 | 69 | 66 | 71 | 68 | 67 | 81 |
78 | 80 | 76 | 67 | 49 | 56 | 45 |
Online | ||||||
79 | 75 | 71 | 81 | 56 | 72 | 49 |
75 | 63 | 81 | 74 | 72 | 71 | 73 |
83 | 59 | 78 | 65 | 53 | 47 | 63 |
82 | 81 | 76 | 65 | 82 | 78 | 76 |
65 | 72 | 85 | 84 | 81 | so | 79 |
Concept used:
Minitab is used.
Calculation:
Since, the
Therefore, the confident interval does not contradict the claim.
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Chapter 10 Solutions
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