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:
- 2
- 10
- 14
- 100
Correct answer: (B)
10
12. The ratio of the standard deviation to the arithmetic mean expressed as a percentage is called:
- Coefficient of standard deviation
- Coefficient of skewness
- Coefficient of kurtosis
- Coefficient of variation
Correct answer: (D)
Coefficient of variation
13. To compare the variation of two or more than two series, we use
- Combined standard deviation
- Corrected standard deviation
- Coefficient of variation
- 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:
- 0
- 4.472
- 4.236
- 2.236
Correct answer: (B)
4.472
15. The moments about mean are called:
- Raw moments
- Central moments
- Moments about origin
- All of the above
Correct answer: (B)
Central moments
16. Moment ratios β1 and β2 are:
- Independent of origin and scale of measurement
- Expressed in original unit of the data
- Unit less quantities
- Both (a) and (c)
Correct answer: (C)
Unit less quantities
17. If the third moment about mean is zero, then the distribution is:
- Positively skewed
- Negatively skewed
- Symmetrical
- Mesokurtic
Correct answer: (C)
Symmetrical
18. If mean=25, median=30 and standard deviation=15, the distribution will be:
- Symmetrical
- Positively skewed
- Negatively skewed
- Normal
Correct answer: (C)
Negatively skewed
19. In a symmetrical distribution, Q3 – Q1 = 20, median = 15. Q3 is equal to:
- 5
- 15
- 20
- 25
Correct answer: (D)
25
20. The degree of peaked ness or flatness of a unimodel distribution is called:
- Skewness
- Symmetry
- Dispersion
- Kurtosis
Correct answer: (D)
Kurtosis