ASRB Agricultural Research Service (ARS) - Agricultural Statistics scientist · India · Agricultural Scientists Recruitment Board (ICAR)
Original practice questions written to the published syllabus · not past papersThe experiments that do not fit a textbook layout: intercropping and its indices, long-term fertiliser and cropping-system trials, animal and changeover feeding trials, repeated measures on the same plants or animals, on-farm and participatory trials, and sensory and laboratory experiments.
In the exams: AICE-JRF Agronomy Unit 6 'statistical analysis for cropping systems including intercropping' (heavy); AICE-JRF Ag Stat Unit 4 crossover designs (present); ASRB NET Ag Stat (reported)
How our questions for ASRB Agricultural Research Service spread across the units of Specialised Agricultural Experiments: Cropping Systems, Animal & On-Farm Trials. Difficulty: 2 easy, 10 medium, 4 hard.
| On-farm and participatory trials | 9 | |
| Cropping-system experiments and system yield equivalents | 1 | |
| Long-term experiments and analysis over time | 1 | |
| Animal experiments: switchover and changeover designs, carry-over effects | 1 | |
| Experiments with livestock: group feeding and pen as the unit | 1 | |
| Experiments in orchards and perennial crops | 1 | |
| Laboratory, greenhouse and pot experiments: pseudo-replication | 1 | |
| Sensory evaluation and panel experiments | 1 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
An unreplicated historic experiment is analysed using treatment x year as error. What must be stated?
C. The assumptions of no persistent plot effects
Such tests assume independence between years and no plot effects; caveats are required.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
Which measurement serves as a covariate in dairy feeding trials?
A. Milk yield in a standardisation period
Pre-treatment yield is unaffected by treatments and correlated with responses.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
Which statement in a broiler trial report is insufficient?
D. n = 400 birds, with no pen numbers given
Without pen numbers readers cannot judge error df or validity.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
In on-farm trials, what usually serves as the block?
C. The farm
Each farm hosts a replicate; many farms provide replication.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
What is a mother-baby trial design?
B. A central researcher trial plus farmer-managed subsets
Snapp's design pairs a replicated mother trial with baby trials of a few treatments.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
Forty farmers each rank four varieties. Which test compares varieties?
C. Friedman's test
Friedman's test analyses ranks within blocks (farmers).
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
Each farmer tests 3 of 10 varieties and ranks them (tricot). Which model estimates variety worth?
B. The Plackett-Luce model
Plackett-Luce handles partial rankings from incomplete sets.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
Why is the farm x treatment interaction important in on-farm trials?
D. It shows how often a technology pays on a farm
Variation in effects across farms informs farmers' risk and targeting.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
Why must pre-treatment measurements be recorded before treatments start?
D. Covariates must not be affected by treatments
A covariate affected by treatment would remove part of the treatment effect.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
In a mother-baby design, what is the main role of the baby trials?
B. Realistic farmer-managed performance and evaluation
Mother trials give precise comparisons; baby trials give realism and farmer feedback.
Further reading: Gomez and Gomez, Statistical Procedures for Agricultural Research; Mead, Curnow and Hasted, Statistical Methods in Agriculture and Experimental Biology
Ten here, 16 in the app. The Laisha app has every practice question we have written to ASRB Agricultural Research Service 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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