Answer:
0.71 = 71% probability that she or he used the lab on a regular basis.
Step-by-step explanation:
Conditional Probability
We use the conditional probability formula to solve this question. It is
In which
P(B|A) is the probability of event B happening, given that A happened.
is the probability of both A and B happening.
P(A) is the probability of A happening.
In this question:
Event A: Student got an A
Event B: Used the lab on a regular basis.
Probability of an student getting an A:
55% of 40%(go to the lab on a regular basis).
15% of 100 - 40 = 60%(do not go to the lab on a regular basis).
So
Probability of getting an A and using the lab on a regular basis:
55% of 40%, so:
Probability that she or he used the lab on a regular basis.
0.71 = 71% probability that she or he used the lab on a regular basis.