Complete Question
Christine has always been weak in mathematics. Based on her performance prior to the final exam in Calculus, there is a 42% chance that she will fail the course if she does not have a tutor. With a tutor, her probability of failing decreases to 12%. There is only a 52% chance that she will find a tutor at such short notice
a What is the probability that Christine fails the course
b Christine ends up failing the course. What is the probability that she had found a tutor? (Round your answer to 4 decimal places.) Probability
Answer:
a
[tex]P(F) = 0.264[/tex]
b
[tex]P(T | F ) = 0.23636 [/tex]
Step-by-step explanation:
From the question we are told that
The probability that Christine will fail the course if she does not have a tutor is [tex]P(F| T') = 0.42[/tex]
The probability that Christine will fail the course if she has a tutor is [tex]P(F| T) = 0.12[/tex]
The probability that she will find a tutor is [tex]P(T) = 0.52[/tex]
Generally the probability that she will not find a tutor is
[tex]P(T') = 1 - 0.52[/tex]
=> [tex]P(T') = 0.48[/tex]
Generally the probability of failing the course is
[tex]P(F) = P(F \ n \ T) + P(F \ n \ T')[/tex]
=> [tex]P(F) = P(F| T) * P(T) + P(A | T') * P(T')[/tex]
=> [tex]P(F) = 0.12 * 0.52 + 0.42* 0.48[/tex]
=> [tex]P(F) = 0.264[/tex]
Generally if Christine ends up failing the course the probability that she had found a tutor? (Round your answer to 4 decimal places.) Probability is mathematically represented as
[tex]P(T | F ) = \frac{ P(F | T) * P(T)}{ P(F)}[/tex]
=> [tex]P(T | F ) = \frac{ 0.12 * 0.52}{ 0.264}[/tex]
=> [tex]P(T | F ) = 0.23636 [/tex]
