Skip to main contentSkip to solution

A random variable X has the following probability distribution:

X-2-10123
P(X)0.10.2k0.32k0.1

then which of the following are TRUE?

(A) k=0.1k=0.1

(B) P(X<1)=0.4P(X < 1) = 0.4

(C) P(X<2)=0.7P(X < 2) = 0.7

(D) P(0<X<3)=0.5P(0 < X < 3) = 0.5

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 3

A probability distribution table has known probabilities and unknown values kk and 2k2k.

All probabilities in a distribution must sum to 11.

Adding all probabilities:

0.1+0.2+k+0.3+2k+0.1=10.1 + 0.2 + k + 0.3 + 2k + 0.1 = 1

0.7+3k=10.7 + 3k = 1

3k=0.33k = 0.3

k=0.1k = 0.1

Statement (A) is TRUE: k=0.1k = 0.1


With k=0.1k = 0.1, the complete probability table is:

X-2-10123
P(X)0.10.20.10.30.20.1

For X<1X < 1, the values are −2,−1,0-2, -1, 0:

P(X<1)=P(X=−2)+P(X=−1)+P(X=0)P(X < 1) = P(X = -2) + P(X = -1) + P(X = 0)

P(X<1)=0.1+0.2+0.1P(X < 1) = 0.1 + 0.2 + 0.1

P(X<1)=0.4P(X < 1) = 0.4

Statement (B) is TRUE.


For X<2X < 2, the values are −2,−1,0,1-2, -1, 0, 1:

P(X<2)=P(X=−2)+P(X=−1)+P(X=0)+P(X=1)P(X < 2) = P(X = -2) + P(X = -1) + P(X = 0) + P(X = 1)

P(X<2)=0.1+0.2+0.1+0.3P(X < 2) = 0.1 + 0.2 + 0.1 + 0.3

P(X<2)=0.7P(X < 2) = 0.7

Statement (C) is TRUE.


For 0<X<30 < X < 3, the values are 1,21, 2 (not including 00 and 33):

P(0<X<3)=P(X=1)+P(X=2)P(0 < X < 3) = P(X = 1) + P(X = 2)

P(0<X<3)=0.3+0.2P(0 < X < 3) = 0.3 + 0.2

P(0<X<3)=0.5P(0 < X < 3) = 0.5

Statement (D) is TRUE.


All statements (A), (B), (C), and (D) are TRUE.

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question