Answer:
C
Step-by-step explanation:
None really
it just keeps going . You keep adding the zero and subtracting.
E [x] = Expected value of X
μ = average
σ = standard deviation
V (X) = Variance
σ = (V(X)) ^ 0.5
E [X] = X * P (x)
Assuming that the number of books purchased is a discrete random variable with mean μ = E [X]
Then the variance of X can be written as V (X) = E [X-μ]^2
We started finding the average μ
μ = 0 * 0.20 + 1 * 0.30 + 2 * 0.50
μ = 1.3
Once the average is found, we can calculate the value of the variance
V (X) = 0.20 * (0-1.3) ^ 2 + 0.30 * (1-1.3) ^ 2 + 0.50 * (2-1.3) ^ 2
V (X) = 0.61
Now we know that from the variance the standard deviation can be obtained by doing:
σ = (V (X)) ^ 0.5
Finally
σ = 0.781
Basically you have to plot the points (x,y) in the graph and just once you plot them all ,look for similarities,for example you could say most of the points are in the same line when you plot them .
600 * 0.85 (the way to work out 85% of something) = 510 flights on time