Answer:
They now should survey 800 people.
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 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)
In this problem:
Same level of confidence, so same z
Same proportion, so same ![\pi](https://tex.z-dn.net/?f=%5Cpi)
We have to change n
We want to reduce the margin of error by half.
M is inverse proportion to the square root of n. That is, as n increases, M decreases.
We want to decrese M by half. So we need to increase n by a factor of 2^2 = 4
The first survey had a sample of 200 people
Increasing by a factor of 4.
200*4 = 800
They now should survey 800 people.
Answer:
3,000M Squared
Step-by-step explanation:
When finding the area of a rectangle, you times the width and the height. After doing so, you will get 30,000CM Squared. Since you need to convert it into meters squared, you <em>divide</em> by 100, which gives you the answer.
6 * 9 = 54
-4 - -1 = 3
So, 54 / 3 = 18!
~ hope this helps/helped!!!
Answer:
THX FOR FREE POINT
Step-by-step explanation:
THANK YOU