X^2 - 7x + 10
= x^2 - 5x - 2x + 10
= x(x - 5 - 2(x - 5}
= (x - 2)(x - 5) = 0
x = 2, 5
Answer:
Now we can calculate the second moment with the following formula:
And replacing we got:
And the variance is given by:
And replacing we got:
And the standard deviation is just the square root of the variance:
Step-by-step explanation:
Previous concepts
For this case we define the random variable X =" how many children the couple will have" and we know the following distribution:
X 1 2 3
P(X) 0.52 0.250 0.230
The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.
The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).
Solution to the problem
For this case we can find the expected value with the following formula:
And replacing we got:
Now we can calculate the second moment with the following formula:
And replacing we got:
And the variance is given by:
And replacing we got:
And the standard deviation is just the square root of the variance:
5(2n – 2) = 5(23n + 10)
10n - 10 = 115n + 50
10n - 115n = 50 + 10
-105n = 60
105n = -60
105n/105 = -60/105
n = -4/7
4,000 +000 +00 + 0 is stander form for four thousand
C.) -3, 1. is the answer because when you look at the graph it’s the only one that doesn’t touch the line through the graph.