Probability and Statistics - Online Test
Q1. Directions: In the following questions two equations numbered I and II are given. You have to solve both the equations.
I. 8x – y = 40
II. 4x + y = 32
I. 8x – y = 40
II. 4x + y = 32
Answer : Option C
Explaination / Solution:
After solving the both equation got values of x = 6 and y = 8
So X
Q2. If the mean of numbers 27,31,89,107,156 is 82 , then the mean of 130,126,68,50,1 is :
Answer : Option B
Explaination / Solution:
mean=130+126+68+50+15=3755=75
Q3. If P (A) = 0.8, P (B) = 0.5 and P(B|A) = 0.4, find P(A|B)
Answer : Option B
Explaination / Solution:
We have ,
P (A) = 0.8, P (B) = 0.5 and P(B|A) = 0.4
P (A) = 0.8, P (B) = 0.5 and P(B|A) = 0.4
Q4. Directions: In the following questions two equations numbered I and II are given. You have to solve both the equations.
I. 4x2 - 24x + 32 = 0
II. y2 = (12)2 – 140
I. 4x2 - 24x + 32 = 0
II. y2 = (12)2 – 140
Answer : Option B
Explaination / Solution:
I. 4x2 - 24x + 32 = 0
x = (4, 2)
II. y = (+2,-2)
So X ≥Y
Q5. If in moderately asymmetrical distribution mode and mean of the data are 6 μ and 9 μ respectively, then median is
Answer : Option A
Explaination / Solution:
median=mode+2mean3=6μ+2(9μ)3=24μ3=8μ
Q6. If P (A) = 0.8, P (B) = 0.5 and P(B|A) = 0.4, find P(A ∪ B)
Answer : Option A
Explaination / Solution:
Q7.
Directions: Study the given information carefully and answer the questions that follow—
A store contains 5 red, 4 blue, 5 green shirts.
If two shirts are picked at random, what is the probability that both are blue?
Answer : Option C
Explaination / Solution:
Probabilities if both are blue
4C2/14C2 = 6/91
Q8. If the mean of the squares of first n natural numbers be 11, then n is equal to
Answer : Option C
Explaination / Solution:
Q9. Evaluate P(A ∪ B), if 2P(A) = P(B) = and P(A|B) =
Answer : Option A
Explaination / Solution:
Q10.
Directions: Study the given information carefully and answer the questions that follow—
A store contains 5 red, 4 blue, 5 green shirts.
If three shirts are picked at random, what is the probability that two are blue and one is red?
Answer : Option A
Explaination / Solution:
Probability if two are Blue and one are Red
[(4C2*5C1)/14C3] = (6*5)/364 -->15/182
