Question

the table below gives the probability density of grades for a particular class. if a student is selected at random, what is the probability that their grade is a c or d? p = ?

Explanation:

Step1: Identify probabilities

The probability of grade C is \(0.27\), and the probability of grade D is \(0.15\).

Step2: Apply addition rule for mutually - exclusive events

Since a student can't have both grade C and grade D simultaneously (mutually - exclusive), we use \(P(C\cup D)=P(C)+P(D)\).

$$P(C\cup D)=0.27 + 0.15$$

$$P(C\cup D)=0.42$$

Answer:

\(0.42\)