What is variance and how it affects the game

1) What is variance in simple words

Variance is a measure of the spread of results around the mean. In games with fixed RTP, two slots with the same expectation can feel very different:

Low variance → frequent small winnings, even balance line.
High dispersion → rare major hits, long empty episodes and deep drawdowns.

The associated quantity is standard deviation (σ): "mean scale of oscillation." The more σ, the "more nervous" the trajectory.

2) Math base: EV, turnover and spread

The expected outcome of the session is' ≈ − edge × Turnover ', where' edge = 1 − RTP '(in fractions), Turnover = rate × number of attempts.

Dispersion of result for N attempts approximately: '± σ × √N' (CPT).

The higher the σ (variance) and the higher the rate share, the more likely the deep drawdown is to reach your goals.

3) How dispersion manifests itself in slots

Hit Frequency (h) - probability of "any win" per spin.

Probability of k empty in a row: 'P ≈ (1 − h) ^ k'.

Example: h = 0. 20 → 10 empty ≈ 0. 8^10 ≈ 10. 7%.

h = 0. 08 → 10 empty ≈ 0. 92^10 ≈ 43%.

Both slots can have RTP of 96%, but in the second (below h) - higher dispersion and longer "silence."

4) Variance and psychology

High dispersion enhances:

tilt (desire to "catch up"), the illusion of debt ("after the series should bonus"), errors in rates (raising% in the midst of the series).
The task is to adjust the bet percentage and duration so that the series normal in statistics do not break the discipline.

5) Mini risk calculators

A. Empty spin series

Given: h and desired "experienced" tail k.

Check: 'BR/rate ≥ k × koef. stock '.

For high-vol, take stock × 1. 5- × 2 (small winnings do not always "heal" the series).

B. Estimation of total spread

Approximation: 'Total ≈ N· EV ± σ·√N'.

For 1:1 roulette, you can count σ one attempt ≈ 1 bet.

For slots, landmarks:

average variance: σ one attempt ≈ 1. 5-3 bets, high: ≈ 3-6 bets.

C. "Price of an hour" (important for tempo)

'Loss _ hour ≈ edge × × rate (attempts/min) × 60 '.

Reduced the speed or rate - reduced the expected minus and the likelihood of "catching" a long tail in one session.

6) How variance affects betting strategy

Rule: the higher the variance, the lower the share of the bankroll rate (BR).

High-vol: 0. 25–0. 75% BR per attempt.

Average: ~ 1% BR.

Low/rates 1:1: 1-2% BR.

The rate should be a percentage of the current BR - this is an automatic rebalance on drawdown/growth.

7) Duration of the dispersion session

High dispersion: short windows (30-60 minutes or 300-600 spins), more pauses, hard stop levels.

Average: 45-90 min or 600-1000 spins.

Low: as long as possible, but remember: longer session → more turnover → closer to − edge × Turnover.

Stop levels (landmarks):

High-vol: SL − 30... − 40 %/TP + 60... + 150% session budget.
Medium: SL −20% / TP +30%.

8) Vager and variance

Wagering is a big turnover, which means dispersion and the risk of bankruptcy until the end of the conditions. To survive:

choose allowed games with lower variance and higher RTP, keep bet 0. 25–0. 5% BR, keep rate limit and exclusions (otherwise progress will not count).

9) Frequent misconceptions

"I'll raise the stake - I'll catch a hit faster." You will raise risk and turnover, not probability.

"After a series of empty slots must give." Independence of outcomes; variance - about scatter, not about debts.

"A long distance will smooth everything out." With EV <0, a long distance will only bring the result closer to the expected minus.

10) Practical presets

A. Quiet playtime (medium variance)

Rate 1% BR, 10-14 sp/min, 60-80 min; SL/TP −20% / +30%; pause 20 min.

B. High-vol "hit hunt"

Bet 0. 25–0. 5% BR, 6-10 sp/min, 30-50 min; SL/TP −30…−40% / +60…+150%; fewer auto-spins.

C. Wager × 35

Bet 0. 25–0. 5% BR, only low/medium variance games allowed; sessions 30-60 min; rate limit control.

11) Checklist "did I consider variance?" (in 60 seconds)

1. Do I know the level of variance and h of the selected game?

2. Rate -% of current BR and corresponds to variance?

3. Delivered SL/TP and session timer?

4. Speed is not "turbo" (I understand the price of an hour) and there are no progressions?

5. For a bonus: I consider 'Bonus × Wager × edge (games)' and fit into the rules?

Dispersion is about the amplitude of your fluctuations around the average. It does not change RTP, but determines the depth of drawdowns, the length of the series and the psychological burden. Manage what is controlled: rate in% of BR, duration and pace, RTP/variance level selection and stop levels. Then even "wild" games will remain entertainment with predictable risk, and not the reason for the breakdown of discipline.