# Question 35811: Probability Variance after Scaling

[Return to catalogue page 180](https://ocme.evemisslab.com/en/questions/page/180/)

[← Question derivation index](https://ocme.evemisslab.com/en/questions/) · [Original question batch](https://ocme.evemisslab.com/en/practice/batch-20261004-advance-20261005-r07-variance-foundations/#q-20261004-advance-20261005-r07-variance-0061)

This teaching derivation has second-context AI mathematical and bilingual semantic review, limited to the model and assumptions stated in this question. It has no human review or new Lean proof and does not promote the original question or MKO to Canonical truth.

R0070-35811 · q-20261004-advance-20261005-r07-variance-0061



## Original question and givens

The nonempty finite sample space is S={0, 1, 2, 3}, with event family F=𝒫(S). The total function X:S→R has table {(0, 0), (1, 0), (2, 12), (3, 1009)}. In the displayed order of S, the nonnegative probability weights are [1/(18), 12/(18), 5/(18), 0/(18)], summing exactly to one. Put Z=(1)X. Find Var(Z)=E[(Z−E[Z])²] exactly as a reduced positive-denominator fraction. This is probability-distribution variance, not sample variance with an n−1 denominator.


- G001 — The nonempty finite sample space is S={0, 1, 2, 3}, with event family F=𝒫(S). The total function X:S→R has table {(0, 0), (1, 0), (2, 12), (3, 1009)}. In the displayed order of S, the nonnegative probability weights are [1/(18), 12/(18), 5/(18), 0/(18)], summing exactly to one. Put Z=(1)X. Find Var(Z)=E[(Z−E[Z])²] exactly as a reduced positive-denominator fraction. This is probability-distribution variance, not sample variance with an n−1 denominator.





## Definition and scope

Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.


- [mko-variance](https://ocme.evemisslab.com/en/mko/mko-variance/)





## Step-by-step derivation

S001 · impliesBefore

source roles = [qf-variance-scale, [F, S, denominator, k, operation, values, weights]]

After

derived = [variance, scale_variance, null]

Conditions: none

Use THIS bank’s actual fields,operation/domain and types.BASE retains permissible extra metadata.Do not import LDL SAFE/set limits or a different bank’s deduplication rules.

Step identifiers and dependenciesRule: R70_SOURCE_bank_specific_interface · Uses: G001





S002 · calculationBefore

Variance ORIGINAL nonnegative RAW weights sum := sum(1, 12, 5, 0)

After

Variance ORIGINAL nonnegative RAW weights sum = 18

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S001





S003 · impliesBefore

source roles = [[0, 1, 2, 3], powerset(S), [0, 0, 12, 1009], [1, 12, 5, 0], 18, 1, null]

After

derived = [Yes]

Conditions: none

Type ALL RAW values/weights EVEN at zero weight.S is nonempty/distinct,F is powerset(S),weights are nonnegative and sum to q>0.Keep values/weights aligned to ORIGINAL S slots;do not sort independently.Type RAW c/k as well.

Step identifiers and dependenciesRule: Variance_WHOLE_normalized_model_ORIGINAL_slot_alignment · Uses: G001, S002





S004 · calculationBefore

Variance transformed ORIGINAL value i=0 := mul(1, 0)

After

Variance transformed ORIGINAL value i=0 = 0

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S003





S005 · calculationBefore

Variance weight times transformed value i=0 := mul(1, 0)

After

Variance weight times transformed value i=0 = 0

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S004





S006 · impliesBefore

source roles = [0, 0, 0, 1, 1, null]

After

derived = [0, 1/18]

Conditions: none

For EACH ORIGINAL slot,set Y=X,X+c or kX while probability remains w/q.Derived values may exceed SAFE and are not recapped as RAW.Zero-weight slots remain in the source but contribute nothing.

Step identifiers and dependenciesRule: Variance_EACH_slot_transformation_preserves_probability · Uses: G001, S005





S007 · calculationBefore

Variance transformed ORIGINAL value i=1 := mul(1, 0)

After

Variance transformed ORIGINAL value i=1 = 0

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S006





S008 · calculationBefore

Variance weight times transformed value i=1 := mul(12, 0)

After

Variance weight times transformed value i=1 = 0

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S007





S009 · impliesBefore

source roles = [1, 1, 0, 12, 1, null]

After

derived = [0, 2/3]

Conditions: none

For EACH ORIGINAL slot,set Y=X,X+c or kX while probability remains w/q.Derived values may exceed SAFE and are not recapped as RAW.Zero-weight slots remain in the source but contribute nothing.

Step identifiers and dependenciesRule: Variance_EACH_slot_transformation_preserves_probability · Uses: G001, S008





S010 · calculationBefore

Variance transformed ORIGINAL value i=2 := mul(1, 12)

After

Variance transformed ORIGINAL value i=2 = 12

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S009





S011 · calculationBefore

Variance weight times transformed value i=2 := mul(5, 12)

After

Variance weight times transformed value i=2 = 60

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S010





S012 · impliesBefore

source roles = [2, 2, 12, 5, 1, null]

After

derived = [12, 5/18]

Conditions: none

For EACH ORIGINAL slot,set Y=X,X+c or kX while probability remains w/q.Derived values may exceed SAFE and are not recapped as RAW.Zero-weight slots remain in the source but contribute nothing.

Step identifiers and dependenciesRule: Variance_EACH_slot_transformation_preserves_probability · Uses: G001, S011





S013 · calculationBefore

Variance transformed ORIGINAL value i=3 := mul(1, 1009)

After

Variance transformed ORIGINAL value i=3 = 1009

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S012





S014 · calculationBefore

Variance weight times transformed value i=3 := mul(0, 1009)

After

Variance weight times transformed value i=3 = 0

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S013





S015 · impliesBefore

source roles = [3, 3, 1009, 0, 1, null]

After

derived = [1009, 0]

Conditions: none

For EACH ORIGINAL slot,set Y=X,X+c or kX while probability remains w/q.Derived values may exceed SAFE and are not recapped as RAW.Zero-weight slots remain in the source but contribute nothing.

Step identifiers and dependenciesRule: Variance_EACH_slot_transformation_preserves_probability · Uses: G001, S014





S016 · calculationBefore

Variance mean numerator sum wY := sum(0, 0, 60, 0)

After

Variance mean numerator sum wY = 60

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S015





S017 · calculationBefore

Variance exact expectation M over q := div(60, 18)

After

Variance exact expectation M over q = 10/3

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S016





S018 · calculationBefore

Variance i=0 Y times q := mul(0, 18)

After

Variance i=0 Y times q = 0

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S017





S019 · calculationBefore

Variance i=0 centered integer numerator := sub(0, 60)

After

Variance i=0 centered integer numerator = -60

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S018





S020 · calculationBefore

Variance i=0 centered numerator squared := mul(-60, -60)

After

Variance i=0 centered numerator squared = 3600

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S019





S021 · calculationBefore

Variance i=0 weight times squared numerator := mul(1, 3600)

After

Variance i=0 weight times squared numerator = 3600

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S020





S022 · calculationBefore

Variance i=1 Y times q := mul(0, 18)

After

Variance i=1 Y times q = 0

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S021





S023 · calculationBefore

Variance i=1 centered integer numerator := sub(0, 60)

After

Variance i=1 centered integer numerator = -60

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S022





S024 · calculationBefore

Variance i=1 centered numerator squared := mul(-60, -60)

After

Variance i=1 centered numerator squared = 3600

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S023





S025 · calculationBefore

Variance i=1 weight times squared numerator := mul(12, 3600)

After

Variance i=1 weight times squared numerator = 43200

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S024





S026 · calculationBefore

Variance i=2 Y times q := mul(12, 18)

After

Variance i=2 Y times q = 216

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S025





S027 · calculationBefore

Variance i=2 centered integer numerator := sub(216, 60)

After

Variance i=2 centered integer numerator = 156

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S026





S028 · calculationBefore

Variance i=2 centered numerator squared := mul(156, 156)

After

Variance i=2 centered numerator squared = 24336

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S027





S029 · calculationBefore

Variance i=2 weight times squared numerator := mul(5, 24336)

After

Variance i=2 weight times squared numerator = 121680

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S028





S030 · calculationBefore

Variance i=3 Y times q := mul(1009, 18)

After

Variance i=3 Y times q = 18162

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S029





S031 · calculationBefore

Variance i=3 centered integer numerator := sub(18162, 60)

After

Variance i=3 centered integer numerator = 18102

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S030





S032 · calculationBefore

Variance i=3 centered numerator squared := mul(18102, 18102)

After

Variance i=3 centered numerator squared = 327682404

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S031





S033 · calculationBefore

Variance i=3 weight times squared numerator := mul(0, 327682404)

After

Variance i=3 weight times squared numerator = 0

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S032





S034 · calculationBefore

Variance sum ALL weighted squared numerators := sum(3600, 43200, 121680, 0)

After

Variance sum ALL weighted squared numerators = 168480

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S033





S035 · calculationBefore

Variance denominator q squared := mul(18, 18)

After

Variance denominator q squared = 324

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S034





S036 · calculationBefore

Variance denominator q cubed binary second factor := mul(324, 18)

After

Variance denominator q cubed binary second factor = 5832

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S035





S037 · calculationBefore

Variance probability population centered sum over q cubed := div(168480, 5832)

After

Variance probability population centered sum over q cubed = 260/9

Conditions: none

This step displays the exact original operands and operation.Mul/sub/div have EXACTLY TWO inputs.Keep rational values exact and derived BigInts unbounded;do not force an answer by approximation.

Step identifiers and dependenciesRule: exact_rational_arithmetic · Uses: G001, S036





S038 · impliesBefore

source roles = [[0, 0, 12, 1009], [1, 12, 5, 0], 18, 10/3, 168480, 5832]

After

derived = [260/9, [0, 12], No]

Conditions: none

E[Y]=M/q and Var=Σ(w/q)(Y−M/q)²=C/q³.Every term is nonnegative,so the sum is0 exactly when EVERY positive-weight Y equals the mean,equivalently constancy on positive support.Zero-weight values may differ.This is NOT n−1 sample variance.

Step identifiers and dependenciesRule: Variance_CENTERED_definition_and_positive_support_zero_equivalence · Uses: G001, S037





S039 · impliesBefore

source roles = [scale_variance, 1, null]

After

derived = [260/9]

Conditions: none

Under a shift,the mean also shifts by c,leaving deviations unchanged.Under scaling,the mean scales by k and squared deviations by k²,including negative/zero k.The ACTUAL Y values were fully recomputed;the law does not excuse untyped c/k.

Step identifiers and dependenciesRule: Variance_SHIFT_SCALE_law_with_conditions · Uses: G001, S038









## Reverse checks


- S039 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
- S038 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
- S037 · premise_and_result_audit — Recompute Variance probability population centered sum over q cubed with exact rational arithmetic, not rounded decimals.
- S036 · premise_and_result_audit — Recompute Variance denominator q cubed binary second factor with exact rational arithmetic, not rounded decimals.
- S035 · premise_and_result_audit — Recompute Variance denominator q squared with exact rational arithmetic, not rounded decimals.
- S034 · premise_and_result_audit — Recompute Variance sum ALL weighted squared numerators with exact rational arithmetic, not rounded decimals.
- S033 · premise_and_result_audit — Recompute Variance i=3 weight times squared numerator with exact rational arithmetic, not rounded decimals.
- S032 · premise_and_result_audit — Recompute Variance i=3 centered numerator squared with exact rational arithmetic, not rounded decimals.
- S031 · premise_and_result_audit — Recompute Variance i=3 centered integer numerator with exact rational arithmetic, not rounded decimals.
- S030 · premise_and_result_audit — Recompute Variance i=3 Y times q with exact rational arithmetic, not rounded decimals.
- S029 · premise_and_result_audit — Recompute Variance i=2 weight times squared numerator with exact rational arithmetic, not rounded decimals.
- S028 · premise_and_result_audit — Recompute Variance i=2 centered numerator squared with exact rational arithmetic, not rounded decimals.
- S027 · premise_and_result_audit — Recompute Variance i=2 centered integer numerator with exact rational arithmetic, not rounded decimals.
- S026 · premise_and_result_audit — Recompute Variance i=2 Y times q with exact rational arithmetic, not rounded decimals.
- S025 · premise_and_result_audit — Recompute Variance i=1 weight times squared numerator with exact rational arithmetic, not rounded decimals.
- S024 · premise_and_result_audit — Recompute Variance i=1 centered numerator squared with exact rational arithmetic, not rounded decimals.
- S023 · premise_and_result_audit — Recompute Variance i=1 centered integer numerator with exact rational arithmetic, not rounded decimals.
- S022 · premise_and_result_audit — Recompute Variance i=1 Y times q with exact rational arithmetic, not rounded decimals.
- S021 · premise_and_result_audit — Recompute Variance i=0 weight times squared numerator with exact rational arithmetic, not rounded decimals.
- S020 · premise_and_result_audit — Recompute Variance i=0 centered numerator squared with exact rational arithmetic, not rounded decimals.
- S019 · premise_and_result_audit — Recompute Variance i=0 centered integer numerator with exact rational arithmetic, not rounded decimals.
- S018 · premise_and_result_audit — Recompute Variance i=0 Y times q with exact rational arithmetic, not rounded decimals.
- S017 · premise_and_result_audit — Recompute Variance exact expectation M over q with exact rational arithmetic, not rounded decimals.
- S016 · premise_and_result_audit — Recompute Variance mean numerator sum wY with exact rational arithmetic, not rounded decimals.
- S015 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
- S014 · premise_and_result_audit — Recompute Variance weight times transformed value i=3 with exact rational arithmetic, not rounded decimals.
- S013 · premise_and_result_audit — Recompute Variance transformed ORIGINAL value i=3 with exact rational arithmetic, not rounded decimals.
- S012 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
- S011 · premise_and_result_audit — Recompute Variance weight times transformed value i=2 with exact rational arithmetic, not rounded decimals.
- S010 · premise_and_result_audit — Recompute Variance transformed ORIGINAL value i=2 with exact rational arithmetic, not rounded decimals.
- S009 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
- S008 · premise_and_result_audit — Recompute Variance weight times transformed value i=1 with exact rational arithmetic, not rounded decimals.
- S007 · premise_and_result_audit — Recompute Variance transformed ORIGINAL value i=1 with exact rational arithmetic, not rounded decimals.
- S006 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
- S005 · premise_and_result_audit — Recompute Variance weight times transformed value i=0 with exact rational arithmetic, not rounded decimals.
- S004 · premise_and_result_audit — Recompute Variance transformed ORIGINAL value i=0 with exact rational arithmetic, not rounded decimals.
- S003 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.
- S002 · premise_and_result_audit — Recompute Variance ORIGINAL nonnegative RAW weights sum with exact rational arithmetic, not rounded decimals.
- S001 · premise_and_result_audit — Reverse-audit THIS question’s original operands,roles and necessary premises;reconstruct the next step,without reversing a one-way implication.Numerical/finite-table checking is not formal proof of an arbitrary theorem.Original Q,bilingual sources,MKO,AST,status and history remain preserved.





## Result

260/9

The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.





## This question review and source binding

Review date: 2026-10-26

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.

Source hashes and review receipts
- input commit: 0f7be61e2c22317a4075561dc822c87d881a50db
- original question SHA-256: fd538cd1bba05afcbbdf7353b5504495aa7ca31e52aad07ad15cd2c74d81e29f
- candidate record SHA-256: d690b5d34967c0ee7f6a3461feecb446c36f6e09992682a1be3513e77b85520e
- semantic review receipt SHA-256: 9820ac6529139bd53d516c8bfdfdd41184b0cd52dad69fa433344010db37af80
- question-first witness SHA-256: c9c939762bbd4d3ea3403084c8e95541dc2c7e56eb82fc74eaba8c80a4517dab
- Lean: NOT_RUN · human review: NOT_PERFORMED

[Same-source full JSON](https://ocme.evemisslab.com/data/question-derivations/questions/q-20261004-advance-20261005-r07-variance-0061.json)




