Probability Grades
1. **Problem Statement:** Given the table of grades by gender, we need to find various probabilities related to the students.
2. **Total number of students:** $$74$$ (given in the table).
3. **(a) Probability the student was male:**
$$P(\text{Male}) = \frac{\text{Number of males}}{\text{Total students}} = \frac{20}{74}$$
4. **(b) Probability the student did NOT get a "C":**
Number of students who got "C" = 28
So, number who did NOT get "C" = $$74 - 28 = 46$$
$$P(\text{Not C}) = \frac{46}{74}$$
5. **(c) Probability the student was female AND got a "C":**
Number of females who got "C" = 19
$$P(\text{Female and C}) = \frac{19}{74}$$
6. **(d) Probability the student was male GIVEN they got a "B":**
Number of students who got "B" = 25
Number of males who got "B" = 5
Conditional probability formula:
$$P(\text{Male} | B) = \frac{P(\text{Male and B})}{P(B)} = \frac{5/74}{25/74} = \frac{5}{25} = \frac{1}{5}$$
7. **(e) Probability the student got a "C" GIVEN they are female:**
Number of females = 54
Number of females who got "C" = 19
$$P(C | \text{Female}) = \frac{19}{54}$$
**Final answers:**
(a) $$\frac{20}{74} \approx 0.2703$$
(b) $$\frac{46}{74} \approx 0.6216$$
(c) $$\frac{19}{74} \approx 0.2568$$
(d) $$\frac{1}{5} = 0.2$$
(e) $$\frac{19}{54} \approx 0.3519$$