Statistics · NDA previous year questions

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2013 17 questions

Q1012013 · 11 Aug 2013
The mean of 20 observations is 15. On checking, it was found that two observations were wrongly copied as 3 and 6. If wrong observations are replaced by correct values 8 and 4, then the correct mean is
1. A.15
2. B.15.15
3. C.15.35
4. D.16
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Answer: B
Q1022013 · 11 Aug 2013
The arithmetic mean of the squares of the first $n$ natural numbers is
1. A. $\frac{n ( n + 1 ) ( 2 n + 1 )}{6}$
2. B. $\frac{n ( n + 1 ) ( 2 n + 1 )}{2}$
3. C. $\frac{( n + 1 ) ( 2 n + 1 )}{6}$
4. D. $\frac{( n + 1 ) ( 2 n + 1 )}{3}$
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Answer: C
Q1032013 · 11 Aug 2013
Consider the following statements: 1. Both the regression coefficients have same sign. 2. If one of the regression coefficients is greater than unity, the other must be less than unity. Which of the above statements is/are correct?
1. A.1 only
2. B.2 only
3. C.Both 1 and 2
4. D.Neither 1 nor 2
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Answer: C
Q1042013 · 11 Aug 2013
Which one of the following measures is determined only after the construction of cumulative frequency distribution?
1. A.Arithmetic mean
2. B.Mode
3. C.Median
4. D.Geometric mean
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Answer: C
Q1052013 · 11 Aug 2013
Coefficient of correlation is the measure of
1. A.central tendency
2. B.dispersion
3. C.both central tendency and dispersion
4. D.neither central tendency nor dispersion
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Answer: D
Q1072013 · 11 Aug 2013
What is the variance of the first 11 natural numbers?
1. A.10
2. B.11
3. C.12
4. D.13
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Answer: A
Q1132013 · 11 Aug 2013
Consider the following statements: 1. The algebraic sum of the deviations of a set of $n$ values from its arithmetic mean is zero. 2. In the case of frequency distribution, mode is the value of the variable which corresponds to maximum frequency. Which of the statements given above is/are correct?
1. A.1 only
2. B.2 only
3. C.Both 1 and 2
4. D.Neither 1 nor 2
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Answer: C
Q1182013 · 11 Aug 2013
Consider the following statements: 1. Pie diagrams are suitable for categorical data. 2. The arc length of a sector of a pie diagram is proportional to the value of the component represented by the sector. Which of the statements given above is/are correct?
1. A.1 only
2. B.2 only
3. C.Both 1 and 2
4. D.Neither 1 nor 2
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Answer: C
Q1202013 · 11 Aug 2013
The variance of 20 observations is 5. If each observation is multiplied by 2, then what is the new variance of the resulting observations?
1. A.5
2. B.10
3. C.20
4. D.40
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Answer: C
Q1022013 · 14 Apr 2013
Marks obtained by 7 students in a subject are 30, 55, 75, 90, 50, 60, 39. The number of students securing marks less than the mean marks is
1. A.7
2. B.6
3. C.5
4. D.4
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Answer: D
Q1032013 · 14 Apr 2013
Variance is always independent of the change of
1. A.origin but not scale
2. B.scale only
3. C.both origin and scale
4. D.None of the above
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Answer: A
Q1042013 · 14 Apr 2013
If two lines of regression are perpendicular, then the correlation coefficient r is
1. A.2
2. B. $\frac{1}{2}$
3. C.0
4. D.None of the above
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Answer: C
Q1052013 · 14 Apr 2013
The standard deviation of the observations 5, 5, 5, 5, 5 is
1. A.0
2. B.5
3. C.20
4. D.25
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Answer: A
Q1062013 · 14 Apr 2013
The marks obtained by 13 students in a test are 10, 3, 10, 12, 9, 7, 9, 6, 7, 10, 8, 6, 7. The median of this data is
1. A.7
2. B.8
3. C.9
4. D.10
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Answer: B
Q1072013 · 14 Apr 2013
Consider the following statements : 1. Both variance and standard deviation are measures of variability in the population. 2. Standard deviation is the square of the variance. Which of the above statements is/are correct ?
1. A.1 only
2. B.2 only
3. C.Both 1 and 2
4. D.Neither 1 nor 2
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Answer: A
Q1082013 · 14 Apr 2013
The harmonic mean H of two numbers is 4 and the arithmetic mean A and geometric mean G satisfy the equation $2 A + G^{2} = 27$ . The two numbers are
1. A.6, 3
2. B.9, 5
3. C.12, 7
4. D.3, 1
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Answer: A
Q1092013 · 14 Apr 2013
Consider the following frequency distribution : $Class interval Frequency 0-10 14 10-20 x 20-30 27 30-40 y 40-50 15$ If the total of the frequencies is 100 and mode is 25, then which one of the following is correct ?
1. A. $x = 2 y$
2. B. $2 x = y$
3. C. $x = y$
4. D. $x = 3 y$
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Answer: C