Answer to Question #336388 in Statistics and Probability for Kev

Question

Which one of the following charts represents a probability distribution?

a)

X | P(x)

 0 | 0.1

 1 | 0.2

 2 | 0.4

 3 |  0.1

b)

 X | P(x)

 0 | 0.3

 1 | 0.2

 2 | 0.1

 3 | 0.35

c)

 X | P(x)

 0 | -0.1

 1 | 0.1

 2 | 0.4

 3 | 0.6

d)

 X | P(x)

 0 | 0

 1 | 0

 2 | 1

 3 | 0

Answer 1

$P(x)\ge0, \sum _iP(x_i)=1$

a)

$0.1+0.2+0.4+0.1=0.8\not=1$

b)

$0.3+0.2+0.1+0.35=0.95\not=1$

c)

$P(0)=-0.1<0$

d)

$0+0+1+0=1$

Answer

d)

 X | P(x)

 0 | 0

 1 | 0

 2 | 1

 3 | 0