Concept explainers
(a)
The critical value of t at the confidence level of 99%.
(a)
Answer to Problem 1RE
Solution: The critical value of t at 99% level of confidence for the
Explanation of Solution
Given: The alpha is 0.01 and the size of the sample is
Explanation: For 99% confidence level, the confidence interval has 0.5% for its greater-than
Obtain the critical value of t by using the distribution table of the t-test. Then, look for 17 degrees of freedom in the row and 1% level of significance in the column. The required t-value is the value that intersects this row and column.
The critical value of t with 17 degrees of freedom is obtained as 2.898 from the table.
(b)
The critical value of t at 90% level of confidence.
(b)
Answer to Problem 1RE
Solution: The critical value of t at 90% level of confidence for the sample size of
Explanation of Solution
Given: The alpha is 0.1 and the size of the sample is
Explanation: For 90% confidence level, the confidence interval has 5% for its greater-than probability and 5% for its less-than probability. Hence, the required area is in the right tail of 0.05. Since the sample size is
Obtain the critical value of t by using the distribution table of the t-test. Then, look for 26 degrees of freedom in the row and 10% level of significance in the column. The required t-value is the value that intersects this row and column.
The critical value of t with 26 degrees of freedom is obtained as 1.706 from the table.
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Chapter 9 Solutions
Integrated Review Materials To Accompany Statistics: Informed Decisions Using Data