2
Q:

Find the probability that one ball is white when two balls are drawn at random from a basket that contains 9 red, 7 white and 4 black balls.

A) 18/95 B) 18/190
C) 1/2 D) 91/190

Answer:   D) 91/190



Explanation:

Total number of elementary events = 20C2 ways =190

 

There are 7 white balls out of which one white can be drawn in 7C1 ways and one ball from remaining 13 balls can be drawn in 13C1 ways.

 

So,favourable events = 7C1*13C1

 

Therfore,required probability = (7C1*13C1)/20C2=91/90

Subject: Probability
Q:

Find the range and mode of the data 17, 18, 28, 19, 16, 18, 17, 29, 18

A) 12 and 18 B) 13 and 18
C) 12 and 17 D) 11 and 17
 
Answer & Explanation Answer: B) 13 and 18

Explanation:
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12 878
Q:

Find the standard deviation of {11, 7, 10,13, 9}

A) 1 B) 2
C) 4 D) 5
 
Answer & Explanation Answer: B) 2

Explanation:
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2 667
Q:

A table tennis player, lost 12 games out of 18 games played. Calculate the games won in terms of decimal.

A) 0.667 B) 0.067
C) 0.50 D) 0.333
 
Answer & Explanation Answer: D) 0.333

Explanation:
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2 680
Q:

A sequence a, ax, ax2, ......, axn, has odd number of terms. Then the median is

 

A) axn2+1 B) axn2-1
C) axn-1 D) axn2
 
Answer & Explanation Answer: D) axn2

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3 5006
Q:

The mean of a distribution is 15 and the standard deviation is 5. What is the value of the coefficient variation?

A) 16.66% B) 66.66%
C) 33.33% D) 100%
 
Answer & Explanation Answer: C) 33.33%

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5 814
Q:

If the standard deviation of a population is 3, what would be the population variance?

 

A) 9 B) 6
C) 8 D) 15
 
Answer & Explanation Answer: A) 9

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4 5351
Q:

The variance of a set of data is 169. Then the standard deviation of the data is

 

A) +-13 B) 13
C) 69 D) 84.5
 
Answer & Explanation Answer: B) 13

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3 4507
Q:

If the standard deviation of a population is 10, what would be the population variance?

A) 100 B) 30
C) 5 D) 20
 
Answer & Explanation Answer: A) 100

Explanation:
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