The 100 most visited websites of Nizhny Novgorod

v is visitors from the region over 31 days. The class sets the uncertainty, and the uncertainty sets the significant digits: d = ⌊−lg ε⌋ + 1.

A direct measurement

The counter keeps a regional tally. Three significant digits.

B conversion between measures

The total audience u is measured and shown as is. One significant digit.

C upper bound

The ranking threshold θ = 0.20 gives v < θ u_RU — a consequence of the selection rule, not an assumption.

D estimate from rank

lg v̂ = β₀ + β₁ lg r, r is the place in the list; OLS; σ_LOO is the leave-one-out error in lg, ρ_S the rank correlation of r and v.
Similarweb: β₀ = 9.51, β₁ = −1.24; n = 86, R² = 0.68, σ_LOO = 0.47, ρ_S = −0.76.
Majestic: β₀ = 5.28, β₁ = −0.22; n = 17, R² = 0.01, σ_LOO = 1.21, ρ_S = −0.30.
Tranco: β₀ = 10.78, β₁ = −1.28; n = 20, R² = 0.14, σ_LOO = 1.33, ρ_S = −0.55.
v̂ only where σ_LOO ≤ 0.70; v̂ ≤ med(v), the median of the measured rows of the hundred; sections of national sites and domains that host other sites lie outside the domain of definition.
Δk = k(v̂_−i) − k(v_i), k is the place in the hundred: med |Δk| = 23, max |Δk| = 541.

The ranking includes Nizhny Novgorod sites: those with a local owner, a local newsroom or an office where the site itself is made. A city section of a national or global service — jobs, maps, directories, catalogues, classifieds — is not ranked, even if the service has a branch in the city; otherwise search engines would qualify too. A traffic counter on such a section says nothing about belonging to the city: it reflects how the service keeps statistics, and the largest national services keep no city counters at all. Regional editions of national media with a local newsroom stay in the ranking.