2formula21.mml = 10.6 2formula22.mml = 18.4 s12 = 8.9 s22 = 8.8 n1 = 20 n2 = 13
ID: 3312609 • Letter: 2
Question
2formula21.mml = 10.6 2formula22.mml = 18.4 s12 = 8.9 s22 = 8.8 n1 = 20 n2 = 13 a. Construct the 90% confidence interval for the difference between the population means. Assume the population variances are unknown but equal. (Round all intermediate calculations to at least 4 decimal places and final answers to 2 decimal places.) Confidence interval is to . b. Specify the competing hypotheses in order to determine whether or not the population means differ. H0: 1 2 = 0; HA: 1 2 0 H0: 1 2 0; HA: 1 2 < 0 H0: 1 2 0; HA: 1 2 > 0 c. Using the confidence interval from part a, can you reject the null hypothesis? Yes, since the confidence interval includes the hypothesized value of 0. No, since the confidence interval includes the hypothesized value of 0. Yes, since the confidence interval does not include the hypothesized value of 0. No, since the confidence interval does not include the hypothesized value of 0.
Explanation / Answer
The statistical software output for this problem is:
Two sample T summary confidence interval:
1 : Mean of Population 1
2 : Mean of Population 2
1 - 2 : Difference between two means
(with pooled variances)
90% confidence interval results:
Hence,
90% confidence interval will be:
6.00 to 9.60
H0: 1 2 = 0; HA: 1 2 0
Yes, since the confidence interval does not include the hypothesized value of 0.
Difference Sample Diff. Std. Err. DF L. Limit U. Limit 1 - 2 7.8 1.0605198 31 6.0018688 9.5981312Related Questions
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