ASRB NET - Agricultural Statistics (and Computer Application / Bioinformatics) · India · Agricultural Scientists Recruitment Board (ICAR)
Original practice questions written to the published syllabus · not past papersThe designs real agricultural surveys use: PPS sampling with and without replacement and its estimators, cluster and multistage sampling, double sampling, sampling on successive occasions, randomised response, non-response and imputation.
In the exams: AICE-JRF Ag Stat Unit 5 (heavy: each technique named); UPSC ISS Statistics III (heavy); ASRB NET Ag Stat (heavy)
ASRB NET / ARS Agricultural Statistics
Applied design and estimation for agricultural surveys with these methods.
How our questions for ASRB NET spread across the units of Sampling Theory II: Unequal Probability, Cluster, Multistage & Repeated Sampling. Difficulty: 15 easy, 56 medium, 23 hard.
| Two-stage and multistage sampling | 9 | |
| Variance estimation in complex surveys: linearisation, jackknife and bootstrap | 9 | |
| PPS sampling with replacement: Hansen-Hurwitz estimator | 8 | |
| Sampling without replacement with unequal probabilities: Horvitz-Thompson estimator | 8 | |
| Cluster sampling with equal and unequal clusters | 8 | |
| Sampling on successive occasions and rotation designs | 8 | |
| Non-response: Hansen-Hurwitz call-backs and weighting adjustments | 8 | |
| Imputation methods | 8 | |
| Des Raj and Murthy's estimators; Midzuno-Sen and Rao-Hartley-Cochran schemes | 7 | |
| Double (two-phase) sampling for stratification and for ratio and regression | 7 | |
| Randomised response techniques | 7 | |
| Inverse and adaptive sampling (introduction) | 7 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
In the Midzuno-Sen scheme, how are units selected?
B. First PPS, rest by SRS
This makes the ratio estimator unbiased.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
Clusters of 10 units have intracluster correlation 0.1. What is the design effect?
B. 1.9
1 + (M - 1) rho = 1 + 9 x 0.1 = 1.9.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
Which estimator of the mean per unit suits unequal clusters best?
B. Ratio estimator
The ratio of sampled cluster totals to sampled sizes stabilises estimates when totals vary with size.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
What is the double-sampling regression estimator?
B. y-bar + b(x-bar' - x-bar)
x-bar' is the first-phase mean.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
What is rotation group bias?
C. Responses changing with time in sample
A non-sampling error of rotation designs.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
What is a 4-8-4 rotation pattern?
D. In 4 periods, out 8, in 4
As in the US Current Population Survey.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
500 mailed; 300 respond with mean 40; 50 of 200 non-respondents interviewed with mean 30. What is the Hansen-Hurwitz estimate?
A. 36
(300 x 40 + 200 x 30)/500 = 36.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
Which model estimates each unit's response probability for weighting?
B. A response-propensity model
Usually logistic regression on frame variables.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
What do replicate weights on public-use files allow?
D. Correct variances without design details
Users recompute estimates with each replicate weight.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
Why are ordinary estimators biased in adaptive cluster sampling?
C. Inclusion depends on observed values
Modified HT/HH estimators based on networks are unbiased.
Further reading: Cochran, Sampling Techniques; Sukhatme et al., Sampling Theory of Surveys with Applications
Ten here, 94 in the app. The Laisha app has every practice question we have written to ASRB NET in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
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