we have the following:
Therefore, the answer is 119.66
10. 8x+4y=4. y=mx+b
-8x. -8x
4y=-8x+4
÷4. ÷4. ÷4
y = -2x +1
slope = -2. y-int= 1
11. slope is changing y over changing x
m = (y2 -y1)/(x2-x1) (0,-1) x1 = 0, y1=-1
(-4-(-1))/(-2-0) (-2,-4) x2 = -2, y2 = -4
(-4 + 1) / (-2)
-3/-2 = 3/2 answer is 3/2
12. b because negative cause it flip in x axis and it become flatter because of the fraction.
13. 2y =8-8x
÷2. ÷2 ÷2
y = 4 - 4x
Answer A
14. B
A)
![\overline{x}=911.9](https://tex.z-dn.net/?f=%5Coverline%7Bx%7D%3D911.9)
B) s = 304.2
C)
![911.9\pm172.1](https://tex.z-dn.net/?f=911.9%5Cpm172.1)
To find the sample mean, add all of the data points together and then divide by 12, the number of data points:
(1425+1227+989+697+729+839+729+742+550+626+1449+941)/12 = 10943/12 = 911.9
To find the sample standard deviation, subtract each data point from the mean; square the result; find the average of these; then take the square root.
To construct a confidence interval, first find the z-score that goes along with it:
Convert 95% to a decimal: 0.95
Subtract from 1: 1-0.95 = 0.05
Divide by 2: 0.05/2 = 0.025
Subtract from 1: 1-0.025 = 0.975
Using a z-table (http://www.z-table.com) we see that this value corresponds with a z-score of 1.96.
We use this to calculate the margin of error:
![ME=z*\frac{s}{\sqrt{n}} \\ \\=1.96*\frac{304.2}{\sqrt{12}}=172.1](https://tex.z-dn.net/?f=ME%3Dz%2A%5Cfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%7D%0A%5C%5C%0A%5C%5C%3D1.96%2A%5Cfrac%7B304.2%7D%7B%5Csqrt%7B12%7D%7D%3D172.1)
This gives us the confidence interval
R = l + (3w)/2
Subtract 'l' to both sides:
r - l = (3w)/2
Multiply 2 to both sides:
2r - 2l = 3w
Divide 3 to both sides:
w = (2r - 2l)/3