Practice • Improve • Repeat
Shyam Agrawal 
Welcome back to Part 21 of Module 5, updated for the UPSC ISS 2026 to 2027 cycle. Simpson’s 1/3 Rule upgraded straight lines to parabolas, but it locked us into an even number of intervals. What if the data arrives in groups of 3 or 6? Two formulas answer: Simpson’s 3/8 Rule and the precision … Read more
Welcome back to Part 20 of Module 5, the single most important part of this module, updated for the UPSC ISS 2026 to 2027 cycle. The Trapezoidal Rule draws straight lines and pays for it with an O(h2)O(h^2) error. The upgrade: replace straight lines with parabolas. That upgrade is Simpson’s 1/3 Rule, and hidden inside … Read more
Welcome back to Part 19 of Module 5, updated for the UPSC ISS 2026 to 2027 cycle. In Part 18 we met the mother of all integration rules and watched n=1n = 1 give birth to its first child. Today we study that child in full depth: the Trapezoidal Rule, and more importantly, the concept … Read more
Every question below was asked in a real UPSC ISS interview, drawn from the transcripts of recommended candidates across the last year cycles, lightly generalised. Each carries a one line pointer, not a full answer, because the thinking is the preparation. Week 2 covered the machinery: the ISS officer’s work, the surveys, the indices, GDP, … Read more
Welcome back to Part 18 of Module 5, updated for the UPSC ISS 2026 to 2027 cycle. Part 17 taught us rates of change from tables. Today we learn accumulated areas from tables: Numerical Integration, and it all begins with one master equation, the General Quadrature Formula, also called the Newton Cotes Quadrature Formula. Numerical … Read more
Three stories dominate India’s data landscape as the 2026 interviews approach: Census 2027 is underway with its houselisting phase running right now and caste enumeration coming, the Digital Personal Data Protection Rules were notified in November 2025, and artificial intelligence has entered both the questions and the machinery of statistics. Real boards have asked about … Read more
Welcome to Part 17 and the opening of Module 5, updated for the UPSC ISS 2026 to 2027 cycle. With Modules 1 to 4 behind you, interpolation holds no fear. Now we enter the highest weightage block of the Numerical Analysis unit: calculus without calculators, beginning with Numerical Differentiation. Numerical differentiation evaluates the derivative of … Read more
ISS boards regularly ask candidates to explain statistical ideas in plain language: a p value to a layman, the difference between correlation and causation, why samples work at all. The transcripts prove the pattern: real candidates were asked for practical life examples of the normal distribution, everyday uses of the harmonic mean, which average best … Read more
India’s GDP is estimated by the National Statistical Office by measuring the value added of every sector of the economy, cross checked from the production, income and expenditure sides. On 27 February 2026, the NSO released an entirely new GDP series with base year 2022-23, replacing the 2011-12 base that had stood for over a … Read more
India measures prices and production through three headline indices: the Consumer Price Index for retail prices, the Wholesale Price Index for bulk trade prices, and the Index of Industrial Production for output. In February 2026 the CPI was rebuilt on a new base year of 2024, which makes this the single most interview relevant topic … Read more