<span>The <u>correct answer</u> is:
A) 60% ± 18%.
Explanation:
In a confidence interval, the margin of error is given by z*(</span>σ/√n<span>), where </span>σ<span> is the standard deviation and n is the sample size.
First we <u>find the value of z</u>:
We want a 95% confidence level; 95% = 95/100 = 0.95.
To find the z-score, we first subtract this from 1:
1-0.95 = 0.05.
Divide by 2:
0.05/2 = 0.025.
Subtract from 1 again:
1-0.025 = 0.975.
Using a z-table, we find this value in the middle of the table. The z-score that is associated with this value is 1.96.
Back to our formula for margin of error, we have 1.96(</span>σ<span>/</span>√n<span>). The larger n, the sample size, is, the larger its square root is. When we divide by a larger number, our answer is smaller; this gives us a smaller margin of error.
This means that if we had a small sample size, we would divide by a smaller number, making our margin of error larger. The largest margin of error we have in this question is 18%, so this is our correct answer.</span>
Answer:
the first one is A, the second one is D.
Step-by-step explanation:
For the perimeter you have to multiply by the original dilation number, and for the area, you have to dilate by 2.5
Hope this helps :D
The student made a mistake in Line 1: AC=2, DF=2 AC ≅ DF .
Answer:
25
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 175cm
Standard deviation = 6 cm
Percentage of students below 163 cm
163 = 175 - 2*6
So 163 is two standard deviations below the mean.
By the Empirical rule, 95% of the heights are within 2 standard deviations of the mean. The other 100-95 = 5% are more than 2 standard deviations of the mean. Since the normal distribution is symmetric, 2.5% of them are more than 2 standard deviations below the mean(so below 163cm) and 2.5% are more than two standard deviations above the mean.
2.5% of the students have heights less than 163cm.
Out of 1000
0.025*1000 = 25
25 is the answer
Answer:
The possible way for the initiative to accomplish its goal without exceeding its budget is use 12.5 hectares for planting trees and 12.5 hectares by purchasing land.
Step-by-step explanation:
Let the variable <em>X</em> represent the amount of land used for planting trees and <em>Y</em> represent the amount of land purchased.
The goal of the environmental initiative is to save at least 25 million hectares of rain forest.
That is:
<em>X</em> + <em>Y</em> = 25....(i)
Now it is provided that:
- The cost of planting trees is $ 400 per hectare.
- The cost of purchasing land is $ 260 per hectare.
- The initiative has a budget of $8,250 million.
Using the above data it can be said that:
400<em>X</em> + 260<em>Y</em> = 8250....(ii)
Solve equations (i) and (ii) simultaneously.
![\ \ \ \ x+y=25]\times 260\\400x+260y=8250\\\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\\\\\Rightarrow\\\\260x+260y=6500\\400x+260y=8250\\(-)\_\_\_\_\_\ (-)\_\_\_\_(-)\_\_\_\\\\\Rightarrow\\\\-140x=-1750\\\\x=\frac{1750}{140}\\\\x=12.5](https://tex.z-dn.net/?f=%5C%20%5C%20%5C%20%5C%20x%2By%3D25%5D%5Ctimes%20260%5C%5C400x%2B260y%3D8250%5C%5C%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C_%5C%5C%5C%5C%5CRightarrow%5C%5C%5C%5C260x%2B260y%3D6500%5C%5C400x%2B260y%3D8250%5C%5C%28-%29%5C_%5C_%5C_%5C_%5C_%5C%20%28-%29%5C_%5C_%5C_%5C_%28-%29%5C_%5C_%5C_%5C%5C%5C%5C%5CRightarrow%5C%5C%5C%5C-140x%3D-1750%5C%5C%5C%5Cx%3D%5Cfrac%7B1750%7D%7B140%7D%5C%5C%5C%5Cx%3D12.5)
Then the value of <em>y</em> is:

Thus, the possible way for the initiative to accomplish its goal without exceeding its budget is use 12.5 hectares for planting trees and 12.5 hectares for purchasing land.