Change the threshold, keep the assumptions in view
Why can the percentage change while yardage stays fixed?
The threshold selects a tail of the same assumed normal curve. Its percentage is conditional on this worksheet’s chosen mean and spread; moving a threshold supplies no new evidence about a player or game.
The stored Bo Nix / Kansas City context has no verified event date, sourced scramble efficiency, actual opponent sack rate, analyst transcript, commercial partnership, live odds, or settlement rules. No sample supports the asserted calibration.
Try a worked example
Default inputs give 4 × 5.2 + 1 × 3.7 = 24.5 example yards, with no sack-rate adjustment at 7.4. Threshold 18.0 gives a modeled upper tail of about 71.4%. Raise only the threshold to 24.5: the mean stays 24.5 and the displayed tail becomes 50.0%. This is symmetry of the assumed curve, not a measured success rate.
Understand what the curve represents
NIST describes the normal distribution using its mean and standard deviation. Here the standard deviation is always 11.5. Changing a threshold reads a different area of that curve; it does not fit the curve to observations. NIST: Normal distribution
The model approximates the cumulative function, takes one minus that value, clamps to 1–99%, and rounds to one decimal. Density height is not the probability of an exact rushing-yard total. A plotted curve is not proof that its assumptions have been tested. NIST: Normal distribution
The chart displays only 0–50 yards. At the maximum inputs, the mean can reach 95.2 example yards, outside that window. A mostly empty chart can therefore reflect its fixed plotting range; it does not show that modeled outcomes vanished. The full normal curve also includes values outside the chart.
Its continuous Y > threshold calculation does not resolve integer-yard rules, “18+” versus “over 18,” or a real market’s settlement terms. No current offered price is supplied, so a precise tail percentage alone cannot establish market value.
Separate football definitions from chosen coefficients
NFL statistical guidance distinguishes a rush from a sack or yards lost attempting to pass. The worksheet’s +0.15-yard adjustment per sack-rate percentage point is an authored coefficient, not an NFL scoring rule or demonstrated causal relation. NFL: 2025 Guide for Statisticians
Each designed run contributes a fixed 3.7 yards. The visible run counts and yields are assumptions, not historical measures. A grounded game forecast would need dated observations, clear play classifications, and validation on outcomes not used to select its parameters.
JSON and text retain the selected inputs, hidden designed-run yield, spread, adjustment, clamp, and source links. Reset restores all five fixture controls. Fractional thresholds remain visible in the band text; the mean-minus-threshold gap updates separately.
The cached chart-library view uses density samples every two yards; the offline fallback draws the same assumed curve with a threshold marker. Resizing redraws either view. Neither view has a live feed or verified bookmaker connection.
Sources and further reading