Math Problem Statement

A test was given to a group of students. The grades and gender are summarized below

A

B

C

Total

Male

5

14

6

25

Female

11

16

4

31

Total

16

30

10

56

If one student is chosen at random from those who took the test,

Find the probability that the student got a 'C' GIVEN they are female.

Solution

To find the probability that a randomly chosen student got a 'C' given that they are female, we are looking for a conditional probability.

The formula for conditional probability is:

P(CF)=P(CF)P(F)P(C \mid F) = \frac{P(C \cap F)}{P(F)}

Where:

  • P(CF)P(C \mid F) is the probability of getting a 'C' given the student is female.
  • P(CF)P(C \cap F) is the probability of both being female and getting a 'C'.
  • P(F)P(F) is the probability of being female.

Step 1: Find P(CF)P(C \cap F)

From the table, the number of females who got a 'C' is 4. Since the total number of students is 56, the probability of a female student getting a 'C' is:

P(CF)=456P(C \cap F) = \frac{4}{56}

Step 2: Find P(F)P(F)

The total number of females is 31, so the probability of being female is:

P(F)=3156P(F) = \frac{31}{56}

Step 3: Calculate the Conditional Probability

Now, using the conditional probability formula:

P(CF)=4563156=431P(C \mid F) = \frac{\frac{4}{56}}{\frac{31}{56}} = \frac{4}{31}

So, the probability that the student got a 'C' given they are female is:

P(CF)=431P(C \mid F) = \frac{4}{31}

Would you like further details on this calculation or any additional clarification?


Here are 5 related questions for you to explore further:

  1. What is the probability that a student chosen at random is male?
  2. What is the probability that a student got an 'A' given they are female?
  3. What is the probability that a student chosen at random got a 'B'?
  4. What is the probability that a student got an 'A' given they are male?
  5. What is the probability that a randomly chosen student got either an 'A' or a 'B'?

Tip: When calculating probabilities from tables, always ensure you are clear on whether you're finding an unconditional or conditional probability.

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Math Problem Analysis

Mathematical Concepts

Probability
Conditional Probability

Formulas

Conditional probability formula: P(A | B) = P(A ∩ B) / P(B)

Theorems

Conditional Probability Theorem

Suitable Grade Level

Grades 9-12