Answer:
6/3
Step-by-step explanation:
An integer is a whole number, that is not a fraction. All of the numbers are fractions, but if you simplify them, you see that 6/3=2. 2 is a whole number, and therefore an integer.
(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.
Answer:

Step-by-step explanation:
Here we are given that a polynomial has zeros as 2 , i and -i . We need to find out the cubic polynomial . In general we know that if
are the zeros of the cubic polynomial , then ,
Here in place of the Greek letters , substitute 2,i and -i , we get ,
Now multiply (x-i) and (x+i ) using the identity (a+b)(a-b)=a² - b² , we have ,
Simplify using i = √-1 ,
Multiply by distribution ,
Simplify by opening the brackets ,
Rearrange ,

Step-by-step explanation:
x² + 2x - 63 = 0
(x+9)(x-7)=0
x=-9 x=7