Answer: The mean and standard deviation are 567.2 and 89.88 resp.
Step-by-step explanation:
Since we have given that
For 370 parts per million = 7% = 0.07
For 440 parts per million = 10% = 0.10
For 550 parts per million = 49% = 0.49
For 670 parts per million = 34% = 0.34
So, Mean of the carbon dioxide atmosphere for these trees would be
![E[x]=370\times 0.07+440\times 0.1+550\times 0.49+670\times 0.34=567.2](https://tex.z-dn.net/?f=E%5Bx%5D%3D370%5Ctimes%200.07%2B440%5Ctimes%200.1%2B550%5Ctimes%200.49%2B670%5Ctimes%200.34%3D567.2)
And
![E[x^2]=370^2\times 0.07+440^2\times 0.1+550^2\times 0.49+670^2\times 0.34=329794](https://tex.z-dn.net/?f=E%5Bx%5E2%5D%3D370%5E2%5Ctimes%200.07%2B440%5E2%5Ctimes%200.1%2B550%5E2%5Ctimes%200.49%2B670%5E2%5Ctimes%200.34%3D329794)
So, Variance would be
![Var\ x=E[x^2]-E[x]^2=329794-567.2^2=8078.16](https://tex.z-dn.net/?f=Var%5C%20x%3DE%5Bx%5E2%5D-E%5Bx%5D%5E2%3D329794-567.2%5E2%3D8078.16)
So, the standard deviation would be

Hence, the mean and standard deviation are 567.2 and 89.88 resp.
Answer:
60
Step-by-step explanation:
<C+<D = 180 since they form a straight line
5x+20 +3x = 180
8x+20 = 180
Subtract 20 from each side
8x+20-20 = 180-20
8x = 160
Divide by 8
8x/8 = 160/8
x = 20
We want to find angle D
<D = 3x= 3*20 = 60
Equation~ 5b + (2b - 4) + (3b -6)= 180.
Answer:

Step-by-step explanation:
we know that
When we compare positive fractions with the same numerator, the largest rational number will be the fraction with the lowest denominator
In this problem we have
and 
Both numerator are equal
Compare the denominators

therefore
is the largest rational number
X^2-81=x^2-9^2=(x+9)(x-9)
this is the answer