Answer:
The minimum sample size required for the estimate is 345.
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 Ztable as such z has a pvalue 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.
The standard deviation is known to be 1.8.
This means that ![\sigma = 1.8](https://tex.z-dn.net/?f=%5Csigma%20%3D%201.8)
What is the minimum sample size required for the estimate?
This is n for which M = 0.19. 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)
![0.19 = 1.96\frac{1.8}{\sqrt{n}}](https://tex.z-dn.net/?f=0.19%20%3D%201.96%5Cfrac%7B1.8%7D%7B%5Csqrt%7Bn%7D%7D)
![0.19\sqrt{n} = 1.96*1.8](https://tex.z-dn.net/?f=0.19%5Csqrt%7Bn%7D%20%3D%201.96%2A1.8)
![\sqrt{n} = \frac{1.96*1.8}{0.19}](https://tex.z-dn.net/?f=%5Csqrt%7Bn%7D%20%3D%20%5Cfrac%7B1.96%2A1.8%7D%7B0.19%7D)
![(\sqrt{n})^2 = (\frac{1.96*1.8}{0.19})^2](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%7D%29%5E2%20%3D%20%28%5Cfrac%7B1.96%2A1.8%7D%7B0.19%7D%29%5E2)
![n = 344.8](https://tex.z-dn.net/?f=n%20%3D%20344.8)
Rounding up to the next integer:
The minimum sample size required for the estimate is 345.
Answer:
the root of -1 is -1
Step-by-step explanation:
When multiplied by itself, the root is typically a specified number of times gives a specified number or quantity. So -1 × -1 = -1
So there you go
Answer:
Option A
f(x) = 12.5(1.6)^x
Step-by-step explanation:
The number of gnats the scientists have gathered
At 0 hours, they gathered 12 gnats.
Checking all the options, applying x = 0 makes the index part become 1 (Anything raised to the power zero is 1).
So, we have the following functions
f(x) = 12.5
f(x) = 12.6
f(x) = 6.2
f(x) = 1.6
This has reduced our work, as we can screen out options C and D, they are too far from 12. This leaves us with option A and B.
At 1 hour, they gathered 20 gnats.
Checking options A and B
A. f(x) = 12.5(1.6)
= 20
B. f(x) = 12.6(6.2)
By inspection, 12 × 6 is already 72,
12.6 × 6.2 will be more.
By these, we can conclude that f(x) = 12.5(1.6)^x has the best models the number of gnats the scientists have gathered after the number of hours listed in the given table.
Answer:
+ 11m - 11
Step-by-step explanation:
6m+(m-2)(m+7)+3 = 6m + [ m*m - 14 -2m + 7m] + 3
= 6m + mm - 14 + 5m + 3
= mm + 11m - 11
6m+(m-2)(m+7)+3 =
+ 11m - 11