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:
Answer:
option B
Step-by-step explanation:
(6x^2-x+8) - (x^2+2)
6x^2-x+8 - x^2-2
5x^2-x+6
Answer:
22,29,37,46,56
adding 1, then 2 then 3 and so on
Answer:
4x-1y=3xy
Step-by-step explanation:
because 3-2=1 and add the y on and the do 4x-1y and that will = 3xy
Answer:
x = 90
y = 60
Step-by-step explanation:
Let x = student
Let y = non-student
x + y = 150
4x + 8y = 840 <—— Use elimination/addition ethos for both equations
8 (x + y = 150)
-1 (4x + 8y = 840) <—— Let’s eliminate y
8x + 8y = 1200
+ -4x - 8y = -840
—————————————
4x = 360
x = 90
x + y = 150 <— substitute for x from above
90 + y = 150
- 90 = - 90 <— subtract from both sides
y = 60