Z-Score — Standardized Deviation
How much each number deviates from the expected value
Z-Score shows how much the observed frequency of each Топ-3 lottery number deviates from the expected value in units of standard deviation. A positive Z-Score means the number appears more often than expected, a negative one means less often.
Z-Score analysis of 20 draws for Топ-3: numbers with the highest deviation — Field 2: 5 (Z=2.24). Field 3: 7 (Z=2.98).
Analysis based on 20 draws from to
What is Z-Score?
Mathematical foundations of the method
Z-Score (standardized deviation) is a statistical measure showing how many standard deviations an observed value differs from the expected value.
Formula
Z = (f - E) / σ
- f — observed frequency of the number
- E = n × p — expected frequency (n — number of draws, p = take/totalBalls)
- σ = √(n × p × (1-p)) — standard deviation
Interpretation
In a fair lottery, the Z-Score of all numbers should approach 0 with a large number of draws. Values |Z| > 2 occur for ~5% of numbers, |Z| > 3 — for ~0.3%.