25
Q:

An urn contains 4 white 6 black and 8 red balls . If 3 balls are drawn one by one without replacement, find the probability of getting all white balls.

A) 5/204 B) 1/204
C) 13/204 D) None of these

Answer:   B) 1/204



Explanation:

Let A, B, C be the events of getting a white ball in first, second and third draw respectively, then 

 Required probability = PABC 

PA PBA PCAB

 Now, P(A) = Probability of drawing a white ball in first draw = 4/18 = 2/9

When  a white ball is drawn in the first draw there are 17 balls left in the urn, out of which 3 are white

 PBA=317 

Since the ball drawn is not replaced, therefore after drawing a white ball in the second draw there are 16 balls left in the urn, out of which 2 are white.

 PCAB =216=18

 Hence the required probability = 29×317×18=1204

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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13 989
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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3 739
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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3 732
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 5950
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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5 832
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 6092
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 4946
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

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