Respuesta :
Answer:
• 3. 0.35
,• 4. 0.6
,• 5. 19/22
,• 6. 7/13
,• 7. 0.56
,• 8. 0.6
,• 9. 0.87
Explanation:
Part 3
The total number of students = 100
• The number of students who had a grade of A = 20
,• The number of students who had a grade of B = 15
The probability that a randomly selected student got an A or B:
[tex]P(A\text{ or B)=P(A)+P(B)}=\frac{20}{100}+\frac{15}{100}=\frac{35}{100}=0.35[/tex]The probability that a randomly selected student got an A or B is 0.35.
Part 4
The number of male students who scored an A = 12.
[tex]P(\text{male}|A)=\frac{P(\text{male and scored A)}}{P(scored\text{ A)}}=\frac{\frac{12}{100}}{\frac{20}{100}}=\frac{12}{20}=0.6[/tex]The probability that an "A" student is male is 0.6.
Part 5
The passing grades are A, B, C, and D.
• The number of females who had a passing grade = 8+9+13+8 = 38
• The number of females = 44
[tex]\begin{gathered} P(\text{passing grade|female)=}\frac{\text{P(passing grade and female)}}{P(female)} \\ =\frac{38}{100}\div\frac{44}{100} \\ =\frac{38}{44} \\ =\frac{19}{22} \end{gathered}[/tex]The probability that if a student was female that they got a passing grade is 19/22.
Part 6
The probability of a male student given that they failed.
• The number of students who failed = 7+6 = 13
,• The number of male students who failed = 7
[tex]P(\text{male student|failed)}=\frac{7}{13}[/tex]The probability of a male student given that they failed is 7/13.
Part 7
• The total number of students = 100
,• The number of male students = 56.
[tex]P(\text{male)}=\frac{56}{100}=0.56[/tex]The probability of a randomly selected student being male is 0.56.
Part 8
• The number of female students that got a B = 9.
,• The number of students that got a B = 15
[tex]P(\text{female}|B)=\frac{9}{15}=0.6[/tex]The probability of a female student given that they got a "B" is 0.6.
Part 9
The number of students who passed Mrs. Hardcase's class = 100-13=87
[tex]P(\text{passing)}=\frac{87}{100}=0.87[/tex]The probability of a randomly selected student passing Mrs. Hardcase's class is 0.87.