C. The point estimate of the difference between the two population means is 2.
D. The 90% confidence interval estimate of the difference between the two population means is (1.748, 0.867)
Given that:
Sample 1 mean (x1) = 9
Sample 2 mean (x2) = 7
Sample 1 standard deviation (σ1^2) = 2.28
Sample 2 standard deviation (σ2^2) = 1.79
C. To find point estimate of the difference between the two population means.
sample mean(x1) - sample mean(x 2)
= 9 - 7
= 2
Therefore, point estimate = 2
D. To find 90% confidence interval estimate of the difference between the two population means
90% confidence for 't'
df = (n1 + n2) - 2
= 12-2
= 10
90% confidence with df = 10 is t
t = 1.812
point estimate + 1 - t * [tex]\sqrt{\frac{s^2_{1} }{n_{1} } + \frac{s^2_{2} }{n_{2} } }[/tex]
2 + 1 - 1.812*[tex]\sqrt{\frac{2.28^2}{6} + \frac{1.79^2}{6} }[/tex]
3 - 1.812 *[tex]\sqrt{0.866 + 0.534}[/tex]
1.188 * 0.9305 + 0.7307
(1.748, 0.867)
To learn more about point estimate check the given link
https://brainly.com/question/16256145
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