B. $0.35
since to find the unit rate of one candy bar, you have to divide $350 by 1000 and you get $0.35
the rate is 350/1000 = 0.35/1
Answer:
The 2 option :)
Step-by-step explanation:
The answer is
A. Linda has $1,500 in a bank account that pays 3% annual interest.
Answer:
The sample size required is at least 171
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%7B1-0.95%7D%7B2%7D%20%3D%200.025)
Now, we have to find z in the Ztable as such z has a pvalue of
.
So it is z with a pvalue of
, so ![z = 1.96](https://tex.z-dn.net/?f=z%20%3D%201.96)
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%2A%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.
What sample size is required?
A samle size of at least n is required, in which n is found when ![M = 3, \sigma = 20](https://tex.z-dn.net/?f=M%20%3D%203%2C%20%5Csigma%20%3D%2020)
So
![M = z*\frac{\sigma}{\sqrt{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%2A%5Cfrac%7B%5Csigma%7D%7B%5Csqrt%7Bn%7D%7D)
![3 = 1.96*\frac{20}{\sqrt{n}}](https://tex.z-dn.net/?f=3%20%3D%201.96%2A%5Cfrac%7B20%7D%7B%5Csqrt%7Bn%7D%7D)
![3\sqrt{n} = 20*1.96](https://tex.z-dn.net/?f=3%5Csqrt%7Bn%7D%20%3D%2020%2A1.96)
![\sqrt{n} = \frac{20*1.96}{3}](https://tex.z-dn.net/?f=%5Csqrt%7Bn%7D%20%3D%20%5Cfrac%7B20%2A1.96%7D%7B3%7D)
![(\sqrt{n})^{2} = (\frac{20*1.96}{3})^{2}](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%7D%29%5E%7B2%7D%20%3D%20%28%5Cfrac%7B20%2A1.96%7D%7B3%7D%29%5E%7B2%7D)
![n = 170.7](https://tex.z-dn.net/?f=n%20%3D%20170.7)
Rouding up
The sample size required is at least 171