Answer:
120 brainliest?
Step-by-step explanation:
There are no solutions because no two numbers that add up to six can also add up to four
Answer:
20%
Step-by-step explanation:
The increase is ...
$90 -75 = $15
As a percentage of the original price, that is ...
$15/$75 × 100% = 0.20×100% = 20%
The increase was 20%.
Answer:
The sample size needed is 2401.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.
![\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=%5Cpi%20%5Cpm%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
In which
z is the zscore that has a pvalue of
.
The margin of error of the interval is:
![M = z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
Estimate the sample size needed if no estimate of p is available so that the confidence interval will have a margin of error of 0.02.
We have to find n, for which M = 0.02.
There is no estimate of p available, so we use ![\pi = 0.5](https://tex.z-dn.net/?f=%5Cpi%20%3D%200.5)
![M = z\sqrt{\frac{\pi(1-\pi)}{n}}](https://tex.z-dn.net/?f=M%20%3D%20z%5Csqrt%7B%5Cfrac%7B%5Cpi%281-%5Cpi%29%7D%7Bn%7D%7D)
![0.02 = 1.96\sqrt{\frac{0.5*0.5}{n}}](https://tex.z-dn.net/?f=0.02%20%3D%201.96%5Csqrt%7B%5Cfrac%7B0.5%2A0.5%7D%7Bn%7D%7D)
![0.02\sqrt{n} = 1.96*0.5](https://tex.z-dn.net/?f=0.02%5Csqrt%7Bn%7D%20%3D%201.96%2A0.5)
![\sqrt{n} = \frac{1.96*0.5}{0.02}](https://tex.z-dn.net/?f=%5Csqrt%7Bn%7D%20%3D%20%5Cfrac%7B1.96%2A0.5%7D%7B0.02%7D)
![(\sqrt{n})^{2} = (\frac{1.96*0.5}{0.02})^{2}](https://tex.z-dn.net/?f=%28%5Csqrt%7Bn%7D%29%5E%7B2%7D%20%3D%20%28%5Cfrac%7B1.96%2A0.5%7D%7B0.02%7D%29%5E%7B2%7D)
![n = 2401](https://tex.z-dn.net/?f=n%20%3D%202401)
The sample size needed is 2401.
Y = 1.50x + 4......x = 7
y = 1.50(7) + 4
y = 10.50 + 4
y = 14.50 <===