Answer:
554 executives should be surveyed.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
![\alpha = \frac{1 - 0.95}{2} = 0.025](https://tex.z-dn.net/?f=%5Calpha%20%3D%20%5Cfrac%7B1%20-%200.95%7D%7B2%7D%20%3D%200.025)
Now, we have to find z in the Z-table as such z has a p-value of
.
That is z with a pvalue of
, so Z = 1.96.
Now, find the margin of error M as such
![M = z\frac{\sigma}{\sqrt{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D)
In which
is the standard deviation of the population and n is the size of the sample.
Standard deviation of 3 hours.
This means that ![\sigma = 3](https://tex.z-dn.net/?f=%5Csigma%20%3D%203)
The 95% level of confidence is to be used. How many executives should be surveyed?
n executives should be surveyed, and n is found with
. So
![M = z\frac{\sigma}{\sqrt{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D)
![0.25 = 1.96\frac{3}{\sqrt{n}}](https://tex.z-dn.net/?f=0.25%20%3D%201.96%5Cfrac%7B3%7D%7B%5Csqrt%7Bn%7D%7D)
![0.25\sqrt{n} = 1.96*3](https://tex.z-dn.net/?f=0.25%5Csqrt%7Bn%7D%20%3D%201.96%2A3)
![\sqrt{n} = \frac{1.96*3}{0.25}](https://tex.z-dn.net/?f=%5Csqrt%7Bn%7D%20%3D%20%5Cfrac%7B1.96%2A3%7D%7B0.25%7D)
![(\sqrt{n})^2 = (\frac{1.96*3}{0.25})^2](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%7D%29%5E2%20%3D%20%28%5Cfrac%7B1.96%2A3%7D%7B0.25%7D%29%5E2)
![n = 553.2](https://tex.z-dn.net/?f=n%20%3D%20553.2)
Rounding up:
554 executives should be surveyed.
We can determine the correct graph by finding its roots
x² - 4x - 12 = 0
x² - 6x + 2x - 12 = 0
x(x-6) +2(x-6) = 0
(x+2)(x-6) = 0
This means the roots of the function are x=-2, and x=6 and the graph will cross x axis at these two points. From the given graphs, the graph B seems to cross these points.
So the answer to this question is option B
You mean a square has an AREA of 100 square meters?
The length of 1 side equals square root of 100 = 10 meters.
Therefore perimeter = 4 * 10 = 40 meters.
Answer:
Step-by-step explanation:
nth term = a +(n-1)d
a3 = 116 ; a + 2d = 116 ---------(i)
a7 = 180; a + 6d = 180 -------(ii)
multiply (ii) by -1. so a will be eliminated
a + 2d = 116 ---------(i)
(ii)*-1 <u>-a - 6d = -180</u> -------(ii) { Now add the two equations}
- 4d = -64
d = -64/-4
d = 16
Plug in the value of d in equation (i),
a + 2*16 = 116
a + 32 = 116
a = 116 - 32
a = 84
12th term = 84 + 11* 16 = 84 + 176 = 260