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Question 28513: Random-Variable Value at an Elementary Outcome

On this page
  1. Original question and givens
  2. Definition and scope
  3. Step-by-step derivation
  4. Reverse checks
  5. Result
  6. This question review and source binding

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R0056-28513 · q-20261004-advance-20261005-r05-random-variable-0013

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, -12), (1, -12), (2, 14), (3, 14)}. Find X(0), reading only the function value without assigning unspecified probabilities.

  • 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, -12), (1, -12), (2, 14), (3, 14)}. Find X(0), reading only the function value without assigning unspecified probabilities.

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.

Step-by-step derivation

S001 · implies

Before

source roles = [qf-random-variable-evaluation, rv_evaluate]

After

derived = [value_at_original_outcome]

Conditions: none

Use the declared scalar/set/Yes-No/fraction answer role;integer fractions retain/1.Do not add an undeclared domain or change original bilingual data,formulas or questions.

Step identifiers and dependencies

Rule: R56_source_answer_role_and_EXACT_family_interface · Uses: G001

S002 · implies

Before

source roles = [[0, 1, 2, 3], powerset(S), [-12, -12, 14, 14]]

After

derived = [[[0, -12], [1, -12], [2, 14], [3, 14]]]

Conditions: none

Align each value with the ORIGINAL S slot,not independently sorted columns.The full powerset contains every preimage of this real-valued function,hence measurability.No invented uniform weights are needed for a value,range or event.

Step identifiers and dependencies

Rule: RV_full_powerset_measurability_ORIGINAL_outcome_value_alignment · Uses: G001, S001

S003 · implies

Before

source roles = [0, [[0, -12], [1, -12], [2, 14], [3, 14]]]

After

derived = [0, -12]

Conditions: none

First require s in S,then use its ORIGINAL slot to read X(s),not the same numeric index after sorting.

Step identifiers and dependencies

Rule: RV_evaluate_actual_member_and_raw_slot · Uses: G001, S002

Reverse checks

  • S003 · premise_and_result_audit — Reverse-check EACH original datum and premise,retaining indices,signs and strict/non-strict boundaries.A correct final answer cannot replace the derivation obligations.This is candidate teaching/exact checking,not formal proof or publication clearance.
  • S002 · premise_and_result_audit — Reverse-check EACH original datum and premise,retaining indices,signs and strict/non-strict boundaries.A correct final answer cannot replace the derivation obligations.This is candidate teaching/exact checking,not formal proof or publication clearance.
  • S001 · premise_and_result_audit — Reverse-check EACH original datum and premise,retaining indices,signs and strict/non-strict boundaries.A correct final answer cannot replace the derivation obligations.This is candidate teaching/exact checking,not formal proof or publication clearance.

Result

-12

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: 3447cd6bd2b0673ad4e9d85c48532164548d1882fe92b78605aee3719169c9af
  • candidate record SHA-256: 3f42876fd7de96fac5bffff18afd8f10b9daf55ce5b5197ed909ba26977dd74e
  • semantic review receipt SHA-256: 8bbda4edbed7078634ae88342998c79bcfb95de96187fac119c3b08e0adb0bc8
  • question-first witness SHA-256: 3edafa72d63d16a22414892b55806430e0a25b15b926d04f312550179607759f
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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