Question

a) What are the 3 requirements that must be met in order for a table to describe a probability distribution? Be specific.

b) Determine whether the following table describes a probability distribution. If your answer is no, identify the requirement that is not  
satisfied.

Response	P(x)
E-mail	0.06
In person	0.55
Instant message	0.24
Text message	0.15

Answer 1

(a)

Requirements for a probability distribution:

(i) All probabilities must be between 0 and 1 (both inclusive)

(ii) The sum of the probabilities must add up to 1

(iii) The probability for a particular value or range of values must be between 0 and 1.

(b)

Answer :

Yes

All the requirements are satisfied:

(i) All probabilities must be between 0 and 1 (both inclusive):

Explanation:

0.06, 0.55, 0.24, 0.15 are each between 0 and 1

(ii) The sum of the probabilities must add up to 1

Explanation:

The sum of the probabilities = 0.06 +0.55+ 0.24 + 0.15 = 1

(iii) The probability for a particular value or range of values must be between 0 and 1.

Explanation:

0.06, 0.55, 0.24, 0.15 are each between 0 and 1 and also range of values are each between 0 and 1