91Ó°ÊÓ

The following table shows the age distribution of senators in the United States Congress as of Fall 2013.

An event's probability ranges from 0 to 1, and both are inclusive.

Probability's special addition rule P(A or B ) =P(A) + P(B)

There are 100 senators in all.

Senators aged 50 and over, i.e. 50-59, 60-69, 70-79, and 80 and up, make up the majority of the United States Senate.

To determine the likelihood that a particular US senator is 50 years old or older.

Make use of the formula.

$P(AorB)=P\left(A\right)+P\left(B\right)$

$$\begin{gathered} P(Senator50yearoldorover)=P(50-59)+P(60-69)+P(70-79) \\ +P(80orover) \\ AsP(50-59)=0.33,P(60-69)=0.32,P(70-79)=0.18 \\ \&P(80orover)=0.05 \\ P(Senator50yearsoldorover)=0.33+0.32+0.18+0.05 \\ P(Senator50yearsoldorover)=0.88 \end{gathered}$$

The probability of an event lie between 0 to 1 and both are inclusive.

There are 100 senators in all.

Number of senators under the age of 70, i.e. under 50, 50-59, and 60-69.

To determine the likelihood that a particular US senator is under the age of 70.

Make use of the formula.

$$\begin{gathered} P(AorB)=P\left(A\right)+P\left(B\right) \\ P(Senator70yearold)=P(Under50)+P(50-59)+P(60-69) \\ AsP(Under50)=0.12,P(50-59)=0.33,P(60-69)=0.32 \\ P(Senator70yearsold)=0.12+0.33+0.32 \\ P(Senator70yearsold)=0.77 \end{gathered}$$