Topic: Chapter 8: Statistics And Probability (Test 1)



Topic: Chapter 8: Statistics And Probability
Q.1
Which of the following is not a measure of dispersion?
A. Range
B. Standard deviation
C. Arithmetic mean
D. Variance
Answer : Option C
Explaination / Solution:
No Explaination.


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Q.2
The range of the data 8, 8, 8, 8, 8 . . . 8 is
A. 0
B. 1
C. 8
D. 3
Answer : Option A
Explaination / Solution:

Range = L - S = 8 - 8 = 0
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Q.3
The sum of all deviations of the data from its mean is
A. always positive
B. always negative
C. zero
D. non-zero integer
Answer : Option C
Explaination / Solution:


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Q.4
The mean of 100 observations is 40 and their standard deviation is 3. The sum of squares of all deviations is
A. 40000
B. 160900
C. 160000
D. 30000
Answer : Option B
Explaination / Solution:


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Q.5
Variance of first 20 natural numbers is
A. 32.25
B. 44.25
C. 33.25
D. 30
Answer : Option C
Explaination / Solution:


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Q.6
The standard deviation of a data is 3. If each value is multiplied by 5 then the new variance is
A. 3
B. 15
C. 5
D. 225
Answer : Option D
Explaination / Solution:


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Q.7
If the standard deviation of x, y, z is p then the standard deviation of 3x + 5 , 3y + 5 , 3z + 5 is
A. 3p + 5
B. 3p
C. p + 5
D. 9p + 15
Answer : Option B
Explaination / Solution:


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Q.8
If the mean and coefficient of variation of a data are 4 and 87.5% then the standard deviation is
A. 3.5
B. 3
C. 4.5
D. 2.5
Answer : Option A
Explaination / Solution:


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Q.9
Which of the following is incorrect?
A. P (A) > 1
B. 0 ≤ P (A) ≤ 1
C. P(ɸ) = 0
D. P (A) + P () = 1
Answer : Option A
Explaination / Solution:
No Explaination.


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Q.10
The probability a red marble selected at random from a jar containing p red, q blue and r green marbles is
A.
B.
C.
D.
Answer : Option B
Explaination / Solution:


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