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:
win
There are 3 face cards / suit. Every suit contains a Jack, Queen, and king.
There are 4 suits so the number of face cards is 3*4 = 12
There is 1 ace / suit
There are 4 suits so the number of aces is 1 * 4 = 4
The gain from the face cards = 12 * 13 = 156
The gain from the aces = 4 * 3 = 12
Total gain = 168
Losses
Any other card costs you $5
How many cards is that? 52 - 16 = 36
Each one costs 5 dollars
Total loss = 5 * 36 = 180
So each time you play the game, you can expect to lose 180 - 68 = 12 dollars. You should walk away quickly from this one.
Sum of angles in a triangle is 180°
90 + (x + 15) + (2x) = 180
90 + x + 15 + 2x = 180
105 + 3x = 180
3x = 180 - 105
3x = 75
x = 75 ÷ 3
x = 25
Smaller angle = x + 15 = 25 + 15 = 40°
Larger angle = 2x = 2(25) = 50°
Answer: 50°
<u>Statement Reason </u>
AB║CD , AD║CB Given
m∠BAC = m∠ACD Alternate Interior Angles
m∠ACB = m∠CAD Alternate Interior Angles
AC = AC Reflexive Property of Equality
ΔABC ≅ΔCDA ASA ≅
Answer:
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Step-by-step explanation:
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