### Business Statistics

11. S.D(X) = 6 and S.D(Y) = 8. If X and Yare independent random variables, then S.D(X-Y) is:

1. 2
2. 10
3. 14
4. 100
Correct answer: (B)
10

12. The ratio of the standard deviation to the arithmetic mean expressed as a percentage is called:

1. Coefficient of standard deviation
2. Coefficient of skewness
3. Coefficient of kurtosis
4. Coefficient of variation
Correct answer: (D)
Coefficient of variation

13. To compare the variation of two or more than two series, we use

1. Combined standard deviation
2. Corrected standard deviation
3. Coefficient of variation
4. Coefficient of skewness
Correct answer: (C)
Coefficient of variation

14. If standard deviation of the values 2, 4, 6, 8 is 2.236, then standard deviation of the values 4, 8,12, 16 is:

1. 0
2. 4.472
3. 4.236
4. 2.236
Correct answer: (B)
4.472

15. The moments about mean are called:

1. Raw moments
2. Central moments
3. Moments about origin
4. All of the above
Correct answer: (B)
Central moments

16. Moment ratios β1 and β2 are:

1. Independent of origin and scale of measurement
2. Expressed in original unit of the data
3. Unit less quantities
4. Both (a) and (c)
Correct answer: (C)
Unit less quantities

17. If the third moment about mean is zero, then the distribution is:

1. Positively skewed
2. Negatively skewed
3. Symmetrical
4. Mesokurtic
Correct answer: (C)
Symmetrical

18. If mean=25, median=30 and standard deviation=15, the distribution will be:

1. Symmetrical
2. Positively skewed
3. Negatively skewed
4. Normal
Correct answer: (C)
Negatively skewed

19. In a symmetrical distribution, Q3 – Q1 = 20, median = 15. Q3 is equal to:

1. 5
2. 15
3. 20
4. 25
Correct answer: (D)
25

20. The degree of peaked ness or flatness of a unimodel distribution is called:

1. Skewness
2. Symmetry
3. Dispersion
4. Kurtosis
Correct answer: (D)
Kurtosis
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