76.3k views
3 votes
CONDITIONAL PROBABILITY ASSISTANCE

CONDITIONAL PROBABILITY ASSISTANCE-example-1

1 Answer

2 votes

Consider such events:

A - selected student is freshmen

B - selected student is girl


A\cap B - selected student is freshman is girl


A|B - choosen girl is freshmen.

Use formula
Pr(A|B)=(Pr(A\cap B))/(Pr(B)).

From the table you can see that girls that are freshmen are 4 from all 30 people, then
Pr(A\cap B)=(4)/(30). There are 18 girls, then
Pr(B)=(18)/(30). Substitute into the formula:


Pr(A|B)=((4)/(30) )/((18)/(30) )=(4)/(18) =(2)/(9).

Answer:
Pr(A|B)=(2)/(9).

User Chococroqueta
by
7.5k points