Anomaly Formula: Amount By Average

What it does:
This rule compares your most recent usage to the average value of all previous usages. If the difference between the most recent value and the average exceeds your defined threshold, and it matches the direction you’re monitoring (increase, decrease, or any), then it’s considered an anomaly.

When to use it:
Use this formula when you want to track deviations from your typical usage over time. It helps you catch significant shifts from your average behavior, such as unexpected spikes or drops.

Mathematical Formula:

Let:

• L = Latest Value
• A = Average of previous values
• T = Threshold
• D = |L − A| (absolute difference)

Anomaly Condition:

D = |L − A| ≥ T

Direction Validation (based on Change Type):

• If Change Type = Increased, condition is valid only if  L > A
• If Change Type = Decreased, condition is valid only if  L < A
• If Change Type = Any, direction check is not required

Outcomes:

❌ Anomaly Detected → D ≥ T and direction matches Change Type
☑️ Skipped → D ≥ T, but direction does not match Change Type
✅ Normal → D < T

Examples:

Example 1

Change Type: Increased
Threshold: 30
History: 100, 120, 110

• If Latest Value = 125
  Result: Normal ✅
  Explanation:
     Average: (100 + 120 + 110) ÷ 3 = 110
     Change: 125 − 110 = 15
     Absolute Difference (15) < Threshold (30)

• If Latest Value = 145
  Result: Anomaly Detected ❌
  Explanation:
    Average: 110
  Change: 145 − 110 = 35
  Absolute Difference (35) ≥ Threshold (30)

•  If Latest Value = 80
  Result: Skipped ☑️
  Explanation:
    Average: 110
    Change: 80 − 110 = −30
    Absolute Difference (30) ≥ Threshold (30)
    But direction = Decrease → does not match “Increased”

Example 2
Change Type: Decreased
Threshold: 20
History: 300, 280, 290

• If Latest Value = 275
  Result: Normal ✅
  Explanation:
    Average: (300 + 280 + 290) ÷ 3 = 290
    Change: 275 − 290 = −15
    Absolute Difference (15) < Threshold (20)

• If Latest Value = 250
  Result: Anomaly Detected ❌
  Explanation:
    Average: 290
    Change: 250 − 290 = −40
    Absolute Difference (40) ≥ Threshold (20)

• If Latest Value = 310
  Result: Skipped ☑️
  Explanation:
    Average: 290
    Change: 310 − 290 = 20
    Absolute Difference (20) ≥ Threshold (20)
    But direction = Increase → does not match “Decreased”

Example 3
Change Type: Any
Threshold: 25
History: 200, 210, 190

• If Latest Value = 220
  Result: Normal ✅
  Explanation:
    Average: (200 + 210 + 190) ÷ 3 = 200
    Change: 220 − 200 = 20
    Absolute Difference (20) < Threshold (25)

• If Latest Value = 240
  Result: Anomaly Detected ❌
  Explanation:
    Average: 200
    Change: 240 − 200 = 40
    Absolute Difference (40) ≥ Threshold (25)