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HW Specic Instructions 1. For the probability problems include the appropriate p

ID: 3175214 • Letter: H

Question

HW Specic Instructions
1. For the probability problems include the appropriate probability statements [Ex. P(A|B), P(X = 15), P(3 X < 5), etc.]
2. Use appropriate notation.
3. ALL probabilities MUST be reported in 4 decimal digits.
4. When using the calculator to compute probabilities/percentiles, provide the calculator function and its arguments.
Suppose the variable Q has the following distribution:

q

1

4

7

10

P(Q= q)

0.1

0.4

0.2

C


(a) Compute the value of C.

(b) Compute the expected value of Q.

(c) Compute the variance of Q.

(d) Compute the standard deviation of Q.

(e) Suppose that M(Q) = 100 4 Q.

i. Compute the expected value of M(Q).

ii. Compute the variance of M(Q).

q

1

4

7

10

P(Q= q)

0.1

0.4

0.2

C

Explanation / Answer

a) for it top be valid pdf sum of all probabilty should equal to 1

0.1+0.4+0.2+C=1

C=0.3

b)expected value =E(Q) =1*0.1+4*0.4+7*0.2+10*0.3=6.1

c)E(Q2) =12*0.1+42*0.4+72*0.2+102*0.3 =46.3

hence variance =Var(Q) =(E(Q2)-(E(Q))2 =9.09

d)Std deviation =SD(Q) =(Var(Q))1/2 =3.015

e)(i) E(M)=100-4*E(Q)) =100-4*6.1=75.6

(ii) Var(M)=(4*SD(Q))2 =(4*3.015)2 =145.44