CK-12 Probability and Statistics - Advanced

7.5. Sums and Differences of Independent Random Variables http://www.ck12.org

TABLE7.23:(continued)

Outcome Probability

NSN ( 0. 76 )( 0. 24 )( 0. 76 ) =. 138624

SNN ( 0. 24 )( 0. 76 )( 0. 76 ) =. 138624

NSS ( 0. 76 )( 0. 24 )( 0. 24 ) =. 043776

SNS ( 0. 24 )( 0. 76 )( 0. 24 ) =. 043776

SSN ( 0. 24 )( 0. 24 )( 0. 76 ) =. 043776

SSS ( 0. 24 )( 0. 24 )( 0. 24 ) =. 013824

TABLE7.24:

Number of Drivers Using a Cell Phone,x Probability,p

0 0. 438976

1 0. 415872

2. 131328

3. 013824

Vocabulary

Expected Value

The mean of the probability distribution for the random variableX. The symbol for expected value isE(X)or

μX.

Probability Distribution

The set of values that a random variable takes on, together with a means of determining the probability of each

value.

Random Variable

A variable that takes on numerical values as the result of a chance.