SOLUTION: Question 2 A.The table below shows the probability distribution for a discrete random variable X. X 0 1 2 4 5 P(X=x) 0.15 0.20 n 0.30 0.10 Table 2. i.State the value of n

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Question 1203397: Question 2
A.The table below shows the probability distribution for a discrete random variable X.
X 0 1 2 4 5
P(X=x) 0.15 0.20 n 0.30 0.10
Table 2.
i.State the value of n (1 mark)
ii.Calculate the expectation value, E(X) (4 marks)
iii.Calculate the variance, Var(X) (5 marks)
B.A random variable X follows a Normal probability distribution and has a mean value of 25 and a variance of 9. Calculate:
i.P(X < 21) (3 marks)
ii.P(X > 26) (3 marks)
iii.P( 23 < X < 28) (4 marks)

Answer by mntnvisions(1)   (Show Source): You can put this solution on YOUR website!
The total probability must be 1.0
Add the probabilities and solve for n.


n=0.25
Mean or average value, use n=0.25 value.


Variance.


B.A random variable X follows a Normal probability distribution and has a mean value of m=25 and a variance of Var=9. Calculate:
Standard deviation = .
i.P(X < 21):


ii.P(X > 26)



iii.P( 23 < X < 28):





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