Question

Which of the following is not a valid probability distribution for a discrete random variable? Check all that apply.

Answer 1

B is one of them, do you have any ideas?

Answer 2

Answer:

Option B and D are correct.

Step-by-step explanation:

We know that Sum of the probability distribution of a discrete random variable is equal to 1.

using this result we check which is not valid probability distribution.

Option A).

Sum of Probability Distribution

$=\frac{1}{5}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}+\frac{1}{5}+\frac{1}{10}+\frac{1}{10}+\frac{1}{10}=\frac{2+1+1+1+2+1+1+1}{10}=\frac{10}{10}=1$

So, This is valid Probability distribution.

Option B).

Sum of Probability Distribution

$=\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+\frac{1}{6}=\frac{20+15+12+10+}{60}=\frac{57}{10}\neq1$

So, This is not a valid Probability distribution.

Option C).

Sum of Probability Distribution

$=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}+\frac{1}{64}+\frac{1}{128}+\frac{1}{128}=\frac{64+32+16+8+4+2+1+1}{128}=\frac{128}{128}=1$

So, This is valid Probability distribution.

Option D).

Given Probability Distribution has negative probability which is not possible.

So, This is not a valid Probability distribution.

Option E).

Sum of Probability Distribution

$=\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}+\frac{1}{6}=\frac{1+1+1+1+1+1}{6}=\frac{6}{6}=1$

So, This is valid Probability distribution.

Therefore, Option B and D are correct.