37 30. The following information is obtained about 1000 students of a college. 400 students were residing in hostel. 80 per cent of the students passed in an examination. 40 per cent of those who failed in the examination were residing in the hostel. Using these data find the coefficient of association between success in examination and residence in the hostel. [Ans. : Q = 0]
Answers
Answer:
Therefore option C is correct
Step-by-step explanation:
Correct option is C)
Given that there are 100 students and only one student passed in all 3 subjects
So the number of students failed in at least one subject is 99
Let a be the number of students failed only in mathematics, b be number of students failed only in physics and c be number of students failed only in Biology.
Let x be number of students failed only in mathematics and physics, y be number of students failed only in physics and biology and z be the number of students failed only in biology and mathematics.
Let p be the number of students failed in all three subjects
By Venn diagram, we get 99=a+b+c+x+y+z+p
Number of students failed in exactly two subjects is 32=x+y+z
Students failed in mathematics is 50=a+x+z+p , students failed in physics is 45=b+x+y+p and students failed in Biology is 40=c+y+z+p
By adding above three equations, we get 135=a+b+c+2(x+y+z)+3p
⇒135=99+32+2p
⇒p=2
Therefore option C is correct
Answer:
option c is correct
Step-by-step explanation:
Of the students in a college, it is known that 60% reside in hostel and 40% day scholars (not residing in hostel). Previous year results report that 30% of all students who reside in hostel attain ‘A’ grade and 20% of day cholars attain ‘A’ grade in their annual examination. At the end of the year, one student is chosen at random from the college and he has an ‘A’ grade, what is the probability that the student is a hosteler?