Answer:
C. 8
the answer is eight or C whatever
Answer:
[See Below]
Step-by-step explanation:

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➜ To solve this, we have to subtract:
➜ To make sure we are correct, we add:
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So your answer would be
.
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ヅ
(a) 404 subjects are needed to estimate the mean HDL cholesterol within 2 points with 99% confidence.
(b) When the confidence level decreases to 95%, the number of subjects decreases from 404 to 234.
<u>Explanation:</u>
Given:
σ = 15.6
Let the number of subjects be n
(a)
When the confidence level is 99%, then z = 2.576
E = 2
We know:
![n = [\frac{z X s}{E}]^2](https://tex.z-dn.net/?f=n%20%3D%20%5B%5Cfrac%7Bz%20X%20s%7D%7BE%7D%5D%5E2)
On substituting the value, we get:
![n = [\frac{2.576 X 15.6}{2} ]^2\\\\n = 403.7](https://tex.z-dn.net/?f=n%20%3D%20%5B%5Cfrac%7B2.576%20X%2015.6%7D%7B2%7D%20%5D%5E2%5C%5C%5C%5Cn%20%3D%20403.7)
Thus, 404 subjects are needed to estimate the mean HDL cholesterol within 2 points with 99% confidence.
(b)
When the confidence level is 95%, then z = 1.96
E = 2
We know:
![n = [\frac{z X s}{E}]^2](https://tex.z-dn.net/?f=n%20%3D%20%5B%5Cfrac%7Bz%20X%20s%7D%7BE%7D%5D%5E2)
On substituting the value, we get:
![n = [\frac{1.96 X 15.6}{2} ]^2\\\\n = 233.7](https://tex.z-dn.net/?f=n%20%3D%20%5B%5Cfrac%7B1.96%20X%2015.6%7D%7B2%7D%20%5D%5E2%5C%5C%5C%5Cn%20%3D%20233.7)
n = 234
Thus, when the confidence level decreases to 95%, the number of subjects decreases from 404 to 234.
The correct answer is A. when solving these graphs the number in the x-axis is always flipped ex: -4 would be +4, and +4 would be -4