ExamBharo · SSC CGL 2024 Tier II — Statistics — 19 January 2025 · exambharo.com/ssc-cgl/previous-year-papers/ssc-cgl-2024-tier-2-statistics-19-jan/
Question paper · SSC CGL
SSC CGL 2024 Tier II — Statistics — 19 January 2025
19 January 2025 · 9:00 AM–11:00 AM81 of the paper’s 100 questions1 per correct answer
Left out of the original paper: 19 (any question that needs a figure, symbol or formatting we cannot show, or whose text or answer did not come through cleanly from the official document).
Questions from the Staff Selection Commission’s paper of 19 January 2025, 9:00 AM–11:00 AM. Each question’s answer is under it, hidden until you open it, and the full answer key is at the end. Take the paper as a timed practice test to be scored.
Statistics
1.

- (a)

- (b)

- (c)

- (d)

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Answer: (d)
- (a)
2. Monthly sales data (in units) shows the following trend-adjusted ratios for three months: January (1.1), February (0.9), and March (1.0). What is the average seasonal index for this quarter?
- (a) 0.95
- (b) 0.9
- (c) 1.0
- (d) 1.1
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Answer: (c)
3. Duncan’s Multiple Range Test makes use of which statistical measure?
- (a) Standard Error of the Means
- (b) Regression Coefficient
- (c) Range Statistic (R)
- (d) F-statistic
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Answer: (c)
4.

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- (b)

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Answer: (c)
- (a)
6. If the critical region is evenly distributed, then the test is referred to as:
- (a) Three tailed
- (b) Zero tailed
- (c) One tailed
- (d) Two tailed
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Answer: (d)
7.

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- (b)

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Answer: (c)
- (a)
8. In a two-way ANOVA, how many hypotheses are tested?
- (a) Three
- (b) One
- (c) Four
- (d) Two
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Answer: (a)
9. In ANCOVA, what happens when the covariate is not linearly related to the dependent variable?
- (a) The results of ANCOVA may be biased.
- (b) The covariate becomes irrelevant.
- (c) All assumptions of ANCOVA are met.
- (d) The F-statistic becomes insignificant.
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Answer: (a)
10. Let X and Y be two independent Poisson variates with rate 5 and 10, respectively, then the E(XY=2) is equal to:
- (a)

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Answer: (b)
- (a)
11.

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Answer: (b)
- (a)
12.

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Answer: (c)
- (a)
13.

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Answer: (d)
- (a)
14.

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Answer: (a)
- (a)
15.

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Answer: (b)
- (a)
17.

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Answer: (c)
- (a)
18.

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Answer: (a)
- (a)
20.

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Answer: (b)
- (a)
22.

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Answer: (c)
- (a)
23. For testing whether two independent Normal populations (with unknown and equal variances) have same mean, one uses:
- (a) t distribution
- (b) Standard Normal Distribution
- (c) Chi Square Distribution
- (d) F distribution
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Answer: (a)
24. The following data represents a time series. Period : 1 2 3 4 5 Observed values : 150 140 160 170 180 Compute the first-order and second-order differences for period 3.
- (a) First-Order: 20, Second-Order: −30
- (b) First-Order: −10, Second-Order: −10
- (c) First-Order: −10, Second-Order: 20
- (d) First-Order: 20, Second-Order: 10
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Answer: (a)
26.

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Answer: (c)
- (a)
27. A model being fitted is said to be adequate if the residual plot:
- (a) is quadratic
- (b) is non-linear
- (c) is U-shaped
- (d) displays random pattern
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Answer: (d)
28.

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Answer: (b)
- (a)
29.

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Answer: (c)
- (a)
30.

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Answer: (a)
- (a)
32.

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Answer: (c)
- (a)
33.

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Answer: (c)
- (a)
34. Level of significance is:
- (a) Probability of Type I Error
- (b) 1 − Probability of Type I Error
- (c) 1 − Probability of Type II Error
- (d) Probability of Type II Error
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Answer: (a)
35.

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Answer: (b)
- (a)
36.

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Answer: (d)
- (a)
37.

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Answer: (b)
- (a)
38. Before using secondary data, one need NOT verify:
- (a) reliability of data
- (b) suitability of data
- (c) expenditure involved at time of collection of data
- (d) adequacy of data
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Answer: (c)
39.

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Answer: (b)
- (a)
41.

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Answer: (a)
- (a)
42.

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Answer: (c)
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43.

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Answer: (d)
- (a)
44.

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Answer: (c)
- (a)
45.

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Answer: (c)
- (a)
46.

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Answer: (a)
- (a)
47. O-gives are NOT useful for locating:
- (a) percentiles
- (b) median
- (c) quartiles
- (d) mean
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Answer: (d)
48.

- (a)

- (b)

- (c)

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Answer: (c)
- (a)
49. Which component of a time series represents short-term fluctuations due to seasonal factors?
- (a) Seasonal component
- (b) Irregular component
- (c) Cyclical component
- (d) Trend
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Answer: (a)
50.

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- (b)

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Answer: (b)
- (a)
51. Which of the following statements is FALSE?
- (a) An alternative hypothesis is complementary to null hypothesis.
- (b) The hypothesis for testing mu < mu0 is two sided / two tailed.
- (c) The null hypothesis H0: mu = mu0 can be tested against the alternative H1: mu not equal to mu0.
- (d) The hypothesis for testing mu > mu0 is one sided / right tailed.
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Answer: (b)
52.

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Answer: (d)
- (a)
53.

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Answer: (a)
- (a)
54.

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Answer: (c)
- (a)
55. If S2 is the sample variance of a sample of size n and s2 is an unbiased estimator of population variance, then which of the following is true?
- (a)

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Answer: (b)
- (a)
56.

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Answer: (a)
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58.

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Answer: (a)
- (a)
59.

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Answer: (b)
- (a)
60. It has been found that 2% of the tools produced by a certain machine are defective. What is the probability that in a shipment of 400 such tools, 3% or more will be defective? (Probability that the normal variate lies between 0 and 1.43 is 0.4236.)
- (a) 0.0764
- (b) 0.50
- (c) 0.4236
- (d) 1.43
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Answer: (a)
62.

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Answer: (a)
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63.

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Answer: (b)
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64.

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Answer: (b)
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65.

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Answer: (a)
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66.

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Answer: (d)
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67.

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Answer: (c)
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68.

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Answer: (d)
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69.

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Answer: (b)
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70.

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Answer: (a)
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74.

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Answer: (d)
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75.

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Answer: (d)
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76.

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Answer: (b)
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77.

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Answer: (c)
- (a)
78. If (X, Y) has a bivariate normal distribution, then X, Y are independent if and only if X, Y are:
- (a)

- (b)

- (c)

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Answer: (b)
- (a)
80. Let X1 , X2 , . . . , X10 be 10 independent and identically distributed (i.i.d) random variables taking the values 0, 1 with corresponding probabilities q, p. Then X = X1 + X2+ . . . + X10 is/has:
- (a) a binomial variate
- (b) Poisson distribution
- (c) a normal variate
- (d) a geometric variate
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Answer: (a)
82.

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Answer: (b)
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83.

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Answer: (d)
- (a)
84. Which of the following is NOT true about collecting data through structured interviews?
- (a) They involve the use of highly standardised techniques of recording.
- (b) The interviewer follows a rigid laid down procedure.
- (c) They involve the use of a set of predetermined questions.
- (d) The sequence of asked questions can be changed.
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Answer: (d)
85.

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Answer: (d)
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86.

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Answer: (c)
- (a)
88. In a one-way ANOVA, which of the following would indicate a violation of the normality assumption?
- (a) Equal variances across groups
- (b) Residuals showing a skewed distribution
- (c) Residuals randomly distributed
- (d) Independent observations
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Answer: (b)
89. What is the main assumption of the ratio-to-moving-averages method?
- (a) Seasonal effects are multiplicative.
- (b) Random components dominate the time series.
- (c) The trend is constant over time.
- (d) The seasonal component is additive.
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Answer: (d)
92.

- (a)

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Answer: (d)
- (a)
93. From a population of a large number of workers with a standard deviation 5, a sample is drawn and the standard error is found to be 0.5. What is the sample size?
- (a) 50
- (b) 1000
- (c) 10
- (d) 100
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Answer: (d)
94.

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Answer: (b)
- (a)
95.

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Answer: (d)
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97.

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Answer: (d)
- (a)
99.

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Answer: (a)
- (a)
100.

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Answer: (c)
- (a)
Show answers
Answer key
Answer key as marked in the Staff Selection Commission’s response sheet. “—” means the sheet did not show it clearly.
Statistics
- Q 1
- (d)
- Q 2
- (c)
- Q 3
- (c)
- Q 4
- (c)
- Q 6
- (d)
- Q 7
- (c)
- Q 8
- (a)
- Q 9
- (a)
- Q 10
- (b)
- Q 11
- (b)
- Q 12
- (c)
- Q 13
- (d)
- Q 14
- (a)
- Q 15
- (b)
- Q 17
- (c)
- Q 18
- (a)
- Q 20
- (b)
- Q 22
- (c)
- Q 23
- (a)
- Q 24
- (a)
- Q 26
- (c)
- Q 27
- (d)
- Q 28
- (b)
- Q 29
- (c)
- Q 30
- (a)
- Q 32
- (c)
- Q 33
- (c)
- Q 34
- (a)
- Q 35
- (b)
- Q 36
- (d)
- Q 37
- (b)
- Q 38
- (c)
- Q 39
- (b)
- Q 41
- (a)
- Q 42
- (c)
- Q 43
- (d)
- Q 44
- (c)
- Q 45
- (c)
- Q 46
- (a)
- Q 47
- (d)
- Q 48
- (c)
- Q 49
- (a)
- Q 50
- (b)
- Q 51
- (b)
- Q 52
- (d)
- Q 53
- (a)
- Q 54
- (c)
- Q 55
- (b)
- Q 56
- (a)
- Q 58
- (a)
- Q 59
- (b)
- Q 60
- (a)
- Q 62
- (a)
- Q 63
- (b)
- Q 64
- (b)
- Q 65
- (a)
- Q 66
- (d)
- Q 67
- (c)
- Q 68
- (d)
- Q 69
- (b)
- Q 70
- (a)
- Q 74
- (d)
- Q 75
- (d)
- Q 76
- (b)
- Q 77
- (c)
- Q 78
- (b)
- Q 80
- (a)
- Q 82
- (b)
- Q 83
- (d)
- Q 84
- (d)
- Q 85
- (d)
- Q 86
- (c)
- Q 88
- (b)
- Q 89
- (d)
- Q 92
- (d)
- Q 93
- (d)
- Q 94
- (b)
- Q 95
- (d)
- Q 97
- (d)
- Q 99
- (a)
- Q 100
- (c)