the table below gives the probability density of grades for a particular class.\ngrade a b c d…

the table below gives the probability density of grades for a particular class.\ngrade a b c d f\nprobability 0.22 0.29 0.27 0.15 0.07\nif a student is selected at random, what is the probability that their grade is an a or b?\np = ?

the table below gives the probability density of grades for a particular class.\ngrade a b c d f\nprobability 0.22 0.29 0.27 0.15 0.07\nif a student is selected at random, what is the probability that their grade is an a or b?\np = ?

Answer

Explanation:

Step1: Identify relevant probabilities

The probability of getting an A is $P(A)=0.22$ and the probability of getting a B is $P(B)=0.29$.

Step2: Use addition rule for mutually - exclusive events

Since a student can't get an A and a B at the same time (mutually - exclusive events), the probability of getting an A or a B is $P(A\cup B)=P(A)+P(B)$. $P(A\cup B)=0.22 + 0.29$ $P(A\cup B)=0.51$

Answer:

$0.51$