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.
Step-by-step explanation:
The way to find missing numbers in equivalent ratios is to multiply the means (the first denominator and the second numerator) and multiply the extremes (the first numerator and the second denominator). It sounds really complicated, but it is quite simple =)
2/5 = x/10
The means in this equivalent ration are 5 and x. The extremes are 2 and 10.
5x = 20
Now solve =)
x = 4
That was pretty simple. Let's move on to the next one. Do exactly the same thing here:
4/10 = 6/x
60 = 4x
15 = x
That was pretty simple, too! Keep going!
6/15 = x/25
15x = 150
x = 10
All of these should be equal, so check them by dividing:
2/5 = 0.4
4/10 = 0.4
6/15 = 0.4
10/25 = 0.4
They all check out, so these are your answers: 2/5, 4/10, 6/15, 10/25
I really hope this helps you =)
(a)

= 400
(b)


(c) Only the positive solution makes sense because you cannot have a negative side length.
(d) Since one side of the painting is 20 inches, all four sides together will be 20*4 = 80 inches
<u><em>Answer:</em></u>
168
<u><em>Explanation:</em></u>
<u>Before we begin, remember the following:</u>
+ve * +ve = +ve -ve * -ve = +ve
+ve * -ve = -ve -ve * +ve = +ve
<u>Now, for the given problem we have:</u>
(-4) * (6) * (-7)
<u>Let's take the first two terms:</u>
(-4) * (6)
Based on the above rules, the product will be negative
<u>Therefore, </u>
(-4) * (6) = -24
<u>Now, the expression became:</u>
(-24) * (-7)
Again, based on the above rule, the product here will be positive
<u>Therefore,</u>
(-24) * (-7) = 168
Hope this helps :)