Answer:
No
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
37 - 56 lb / ft3
0.6 - 0.9 103 kg / m3
Step-by-step explanation:
The density or hardness of wood varies by species, and the value is necessary to approximate the weight of lumber by volume. In this table, the density of different species of wood is expressed as weight in pounds per cubic foot and kilograms per cubic meter. The density will vary based on the moisture content of the wood.
 
        
             
        
        
        
Answer:

Now we can find the second central moment with this formula:

And replacing we got:

And the variance is given by:
![Var(X) = E(X^2) - [E(X)]^2](https://tex.z-dn.net/?f=%20Var%28X%29%20%3D%20E%28X%5E2%29%20-%20%5BE%28X%29%5D%5E2)
And replacing we got:

And finally the deviation would be:

Step-by-step explanation:
We can define the random variable of interest X as the return from a stock and we know the following conditions:
 represent the result if the economy improves
 represent the result if we have a recession
We want to find the standard deviation for the returns on the stock. We need to begin finding the mean with this formula:

And replacing the data given we got:

Now we can find the second central moment with this formula:

And replacing we got:

And the variance is given by:
![Var(X) = E(X^2) - [E(X)]^2](https://tex.z-dn.net/?f=%20Var%28X%29%20%3D%20E%28X%5E2%29%20-%20%5BE%28X%29%5D%5E2)
And replacing we got:

And finally the deviation would be:
