Solution :
a). 
Now, if X = Y, then :

Then, E[X|Y] = x = y
So, 

= 0
Therefore, this statement is TRUE.
b). If X = Y , then Var (X) = Var (Y)
And as Var (X|Y) = 0, so Var (X|Y) ≠ Var (X), except when all the elements of Y are same.
So this statement is FALSE.
c). As defined earlier,

So, this statement is also TRUE.
d). The statement is TRUE because
.
e). FALSE
Because, 
Answer:
3 days
Step-by-step explanation:
First, let's convert 400 meters to km (kilometers):
To find km from m we divide the meters by 1000:
400/1000 = 0.4
Therefore, there are 0.4 km in 1 meter.
Kali runs 10 laps every day, since 1 lap is 0.4 km we can multiply 10 by 0.4 to see how many kilometers they run in 1 day:
(10)(0.4) = 4
Kali runs 4 kilometers every day
Now, we can find how long it will take Kali to run a total of 12 kilometers by dividing 12 by 4
12/4 = 3
It will take Kali 3 days to run a total of 12 kilometers.
<em>I hope this helps!!</em>
<em>- Kay :)</em>
Answer:
5y + 15
Step-by-step explanation:
8y - 6y = 2y + 3y = 5y
13 + 2 = 15
This answer to this question is b
There are many solutions. But what do you mean with a perfect square of a number. I thought a number IS a perfect square or not.
For example, the difference between 2² and 4² = 12, which is twice the number 6, which is √36
The difference between 2² and 6² = 32, which is twice the number 16, which is a perfect square.
So choose depending on your interpretation of the question... ;-)