60％を3回試行と80%を2回試行ではどちらの期待値が高いか
60％を3回の方が高い
すみません、80％を2回の方が高いです。答えの見方を間違えておりました。
本件の最新記事はこちらです。
60％を3回試行と80%を2回試行ではどちらの期待値が高いか→80%を2回の方が高い
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// 60％の成功率を3回チャレンジして2回以上成功する確率を教えて下さいヾ(｡>д<)ﾉ main(); function main() { const p = console.log; const probabilityOf = n => Math.random() * 100 < n; const challenge = (percent, limit, targetCnt, isBool = false) => { let cnt = 0; for (let i = 0; i < limit; i++) { if (probabilityOf(percent)) { if (isBool) { return true; } cnt++; } } if (isBool) { if (cnt === 0) { return false; } } return targetCnt <= cnt; }; const calcProportion = (percent, limit, times) => { let cnt = 0; for (let i = 0; i < times; i++) { if (challenge(percent, limit, 1, true)) { cnt++; } } const proportion = cnt * 100.0 / times; return proportion; }; const dispProportion = (percent, limit, times) => { const proportion = calcProportion(percent, limit, times); let msg = percent + "% に" + limit + "回 挑戦して成功する割合 " + proportion + "% (" + times + "回試行)"; p(msg); }; const calcHitCnt = (percent, limit) => { let cnt = 0; for (let i = 0; i < limit; i++) { if (probabilityOf(percent)) { cnt++; } } return cnt; }; const calcExpectedValue = (percent, limit, times) => { let cnt = 0; for (let i = 0; i < times; i++) { cnt += calcHitCnt(percent, limit); } expectedValue = cnt / times; return expectedValue; }; const dispExpectedValue = (percent, limit, times) => { const expectedValue = calcExpectedValue(percent, limit, times); let msg = percent + "% に" + limit + "回 挑戦した時の期待値 " + expectedValue + "% (" + times + "回試行)"; p(msg); }; const times = 2000000; let percent = 60.0; let limit = 3; dispExpectedValue(percent, limit, times); percent = 80.0; limit = 2; dispExpectedValue(percent, limit, times); } |
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60% に3回 挑戦した時の期待値 1.800217% (2000000回試行) 80% に2回 挑戦した時の期待値 1.600028% (2000000回試行) |
