Explain why this is or is not a probability distribution.

x

1

2

3

4

P (x)

0.2

0.1

0.4

0.2

The sum of p (x) over all possible values of x is 1, that is

∑j pj = 1

where j represents all possible values that x can have and pj is the probability at xj.

yes it is probability distribution

all sum is 0.9

all probability between 0 and 1