Answer:
A. E(x) = 1/n×n(n+1)/2
B. E(x²) = 1/n
Step-by-step explanation:
The n candidates for a job have been ranked 1,2,3....n. Let x be the rank of a randomly selected candidate. Therefore, the PMF of X is given as
P(x) = {1/n, x = 1,2...n}
Therefore,
Expectation of X
E(x) = summation {xP(×)}
= summation {X×1/n}
= 1/n summation{x}
= 1/n×n(n+1)/2
= n+1/2
Thus, E(x) = 1/n×n(n+1)/2
Value of E(x²)
E(x²) = summation {x²P(×)}
= summation{x²×1/n}
= 1/n
Answer:
Step-by-step explanation:
The formula of an area of a rectangle:
l - length
w - width
We have
Substitute:
<em>divide both sides by 15</em>
The formula of a perimeter of a rectangle:
Substitute:
Here: Fraction = 3/5
Let, original fraction (before simplifying) = 3x/5x
Then, 3x + 5x = 40
8x = 40
x = 40/8
x = 5
So, 3x = 3(5) = 15 & 5(5) = 25
In short, Your Answer would be 15/25
Hope this helps!
Answer:
Step-by-step explanation:
b is greater than or equal to 4: 4 ≤ b
and at most 13 : b ≤ 13
4 ≤ b ≤ 13
Draw a small open circle above the number 2 and extend the line
