Concept explainers
a.
To find: The point estimate of the variance of the population.
a.
Answer to Problem 23SE
The point estimate is 900.
Explanation of Solution
Given:
Sample mean
Sample standard deviation
Formula used:
The formula to compute the confidence interval for population standard deviation is:
The formula to compute the confidence interval for the population variance is:
Calculation:
The point estimate of the variance of the population.
Thus, the required estimate is 900.
b.
To find: The 90% confidence interval for the population variance.
b.
Answer to Problem 23SE
The confidence interval is (567, 1690)
Explanation of Solution
Calculation:
Degrees of freedom
The critical values can be calculated as follows:
Substitute the values in the confidence interval formula.
Thus, the obtained confidence interval is (567, 1690)
c.
To find: The 90% confidence interval for the population standard deviation
c.
Answer to Problem 23SE
The confidence interval is (23.8, 41.1)
Explanation of Solution
Calculation:
From the above part, it is known that the confidence interval is (567, 1690)
The confidence interval for the population standard deviationis calculated as:
Thus, the required confidence interval is (23.8, 41.1)
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Chapter 11 Solutions
Essentials of Modern Business Statistics with Microsoft Office Excel (Book Only)
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill