STATISTICSMYSTAT LAB ACCESS CODE + PHS
13th Edition
ISBN: 9780134613949
Author: MCCLAVE
Publisher: PEARSON
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Textbook Question
Chapter 8.2, Problem 8.3LM
In order to compare the means of two populations, independent random samples of 400 observations are selected from each population, with the following results:
Sample 1 | Samlpe 2 |
|
|
s1 = 150 | s2 = 200 |
- a. Use a 95% confidence
interval to estimate the difference between the population means (μ1 – μ2). Interpret the confidence interval. - b. Test the null hypothesis H0 : (μ1 – μ2) = 0 versus the alternative hypothesis H0 : (μ1 – μ2) ≠ 0. Give the significance level of the test and interpret the result.
- c. Suppose the test in part b was conducted with the alternative hypothesis H0 : (μ1 – μ2) > 0. How would your answer to part b change?
- d. Test the null hypothesis H0 : (μ1 – μ2) = 25 versus H0 : (μ1 – μ2) ≠ 25. Give the significance level and interpret the result. Compare your answer with the test conducted in part b.
- e. What assumptions are necessary to ensure the validity of the inferential procedures applied in parts a-d?
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Given two independent samples, with sample sizes n1 = 35 and n2 = 30 and their respective sample means x̄1 = 20 and x̄2 = 22, with standard deviations s1 = 3 and s2 = 4, find the 95% confidence interval for the difference in means (x̄1 - x̄2) using a two-sample t-test.
In order to compare the means of two populations, independent random samples of 400 observations are selected from each population, with the following results: x1 and x2 are sample means; s1 and s2 are sample deviations.
Sample 1
Sample 2
X1 = 6,275
X2 = 6,840
S1 = 350
S2 = 250
Use a 99% confidence interval to estimate the difference between the population means (μ1 – μ2). Interpret the confidence interval.
Test the null hypothesis H0: (μ1 – μ2) = 0 versus the alternative hypothesis Ha: ((μ1 – μ2) ≠ 0. Give the significance level of the test and interpret the result.
Suppose the test in part b was conducted with the alternative hypothesis Ha: (μ1 – μ2) > 0. How would your answer to part b change?
Test the null hypothesis H0: (μ1 – μ2) = 25 versus Ha: (μ1 – μ2) ≠ 25. Give the significance level and interpret the result. Compare your answer to the test conducted in part b.
What assumptions are necessary to ensure the validity of the inferential procedures applied in…
A random sample of size n1=23, taken from a normal population with a standard deviation σ1=5, has a mean x1=77. A second random sample of size n2=37, taken from a different normal population with a standard deviation σ2=3, has a mean x2=38. Find a 96% confidence interval for μ1−μ2.
Chapter 8 Solutions
STATISTICSMYSTAT LAB ACCESS CODE + PHS
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