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.