Asked by Shannon
If a grade was drawn at random from the data shown below, what is the probability that the grade is not a B?
Grade Frequency
A 2
B 8
C 11
D 2
F 1
I think it is 1 out of 5 or 4 but I am not sure? Please help :) Thank you much!
Grade Frequency
A 2
B 8
C 11
D 2
F 1
I think it is 1 out of 5 or 4 but I am not sure? Please help :) Thank you much!
Answers
Answered by
MathMate
There are 5 possible outcomes, one of which is a B.
So what is P(B), and what is P(not B)?
Hint : P(B) and P(not B) have to add up to 1.
So what is P(B), and what is P(not B)?
Hint : P(B) and P(not B) have to add up to 1.
Answered by
Shannon
Oh ok I think I get it, so P(B)=0.5, 1/2,
and P(not B)=0.5,1/2???
Is that right?
and P(not B)=0.5,1/2???
Is that right?
Answered by
MathMate
Sorry, not really.
Figure out the probability of P(B) which is to get B out of 5 possible choices.
The rest would be easy to figure out.
Figure out the probability of P(B) which is to get B out of 5 possible choices.
The rest would be easy to figure out.
Answered by
Jen
Add up all the grades that aren't B's. Then put that over the total amount of grades.
Answered by
Shannon
Ok so it would be P(B)=0.8, the probability that the grade is not a B.?
I hope this is right now, if it isn't I give up....lol !
I hope this is right now, if it isn't I give up....lol !
Answered by
MathMate
Don't give up, you're right.... almost!
What Jen showed you to do was
P(not B), which equals 0.8
("...grades that aren't B's...")
there is only one grade B, so it is 1/5, there are 4 grades that are not B, so
P(not B)=4/5=0.8
Sorry if it was too confusing, hope it's more clear now.
What Jen showed you to do was
P(not B), which equals 0.8
("...grades that aren't B's...")
there is only one grade B, so it is 1/5, there are 4 grades that are not B, so
P(not B)=4/5=0.8
Sorry if it was too confusing, hope it's more clear now.