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The probability distribution of a discrete random variable is given below :

X12345
P(X)1/5m2/52m3m

Which of the following are correct?

A. P(2)=115P(2)=\frac{1}{15}

B. P(4)=215P(4)=\frac{2}{15}

C. P(X<2)=15P(X<2)=\frac{1}{5}

D. P(X≥4)=15P(X\geq4)=\frac{1}{5}

Choose the correct answer from the options given below:

Solution

✅ Correct Option: 1

Probabilities sum to 1: 15+6m+25=1\frac15+6m+\frac25=1, so m=115m=\frac1{15}. Then P(2)=115P(2)=\frac1{15} (A true), P(4)=2m=215P(4)=2m=\frac2{15} (B true), P(X<2)=P(1)=15P(X<2)=P(1)=\frac15 (C true). But P(X≥4)=5m=13P(X\ge4)=5m=\frac13, so D is false.

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