老师，请问本题为什么不能直接算出标准差，即在求发方差时直接用省掉平方，用求标准差的形式，最后省去求出的方差再开根号？-有问必答-品职教育专注CFA ESG FRM CPA 考研等财经培训课程

NO.PZ2017092702000073 问题如下 The probability stribution for a company’s sales is:The stanrviation of sales is closest to: A.$9.81 million. B.$12.20 million. C.$32.40 million. A is correct. The analyst must first calculate expectesales 0.05 × $70 + 0.70 × $40 + 0.25 × $25 = $3.50 million + $28.00 million + $6.25 million = $37.75 million. After calculating expectesales, we ccalculate the varianof sales: = σ2 (Sales) = P($70)[$70 – E(Sales)]2 + P($40)[$40 – E(Sales)]2 + P($25)[$25 – E(Sales)]2 = 0.05($70 – 37.75)2 + 0.70($40 – 37.75)2 + 0.25($25 – 37.75)2 = $52.00 million + $3.54 million + $40.64 million = $96.18 million. The stanrviation of sales is thus σ = ($96.18)1/2 = $9.81 million. 1

2024-04-07 16:29 1 · 回答

NO.PZ2017092702000073 问题如下 The probability stribution for a company’s sales is:The stanrviation of sales is closest to: A.$9.81 million. B.$12.20 million. C.$32.40 million. A is correct. The analyst must first calculate expectesales 0.05 × $70 + 0.70 × $40 + 0.25 × $25 = $3.50 million + $28.00 million + $6.25 million = $37.75 million. After calculating expectesales, we ccalculate the varianof sales: = σ2 (Sales) = P($70)[$70 – E(Sales)]2 + P($40)[$40 – E(Sales)]2 + P($25)[$25 – E(Sales)]2 = 0.05($70 – 37.75)2 + 0.70($40 – 37.75)2 + 0.25($25 – 37.75)2 = $52.00 million + $3.54 million + $40.64 million = $96.18 million. The stanrviation of sales is thus σ = ($96.18)1/2 = $9.81 million. 请问这道题目可以用金融计算器算吗

2023-10-22 22:47 1 · 回答

NO.PZ2017092702000073问题如下The probability stribution for a company’s sales is:The stanrviation of sales is closest to:A.$9.81 million. B.$12.20 million. C.$32.40 million. A is correct. The analyst must first calculate expectesales 0.05 × $70 + 0.70 × $40 + 0.25 × $25 = $3.50 million + $28.00 million + $6.25 million = $37.75 million. After calculating expectesales, we ccalculate the varianof sales: = σ2 (Sales) = P($70)[$70 – E(Sales)]2 + P($40)[$40 – E(Sales)]2 + P($25)[$25 – E(Sales)]2 = 0.05($70 – 37.75)2 + 0.70($40 – 37.75)2 + 0.25($25 – 37.75)2 = $52.00 million + $3.54 million + $40.64 million = $96.18 million. The stanrviation of sales is thus σ = ($96.18)1/2 = $9.81 million. 1.可不可以再一下为啥求均值就是求期望？2.这里的variance为啥不除以总个数？谢谢

2023-06-18 17:51 1 · 回答

NO.PZ2017092702000073 问题如下 The probability stribution for a company’s sales is:The stanrviation of sales is closest to: A.$9.81 million. B.$12.20 million. C.$32.40 million. A is correct. The analyst must first calculate expectesales 0.05 × $70 + 0.70 × $40 + 0.25 × $25 = $3.50 million + $28.00 million + $6.25 million = $37.75 million. After calculating expectesales, we ccalculate the varianof sales: = σ2 (Sales) = P($70)[$70 – E(Sales)]2 + P($40)[$40 – E(Sales)]2 + P($25)[$25 – E(Sales)]2 = 0.05($70 – 37.75)2 + 0.70($40 – 37.75)2 + 0.25($25 – 37.75)2 = $52.00 million + $3.54 million + $40.64 million = $96.18 million. The stanrviation of sales is thus σ = ($96.18)1/2 = $9.81 million. 答案解析第二步不明白

2023-05-26 00:04 1 · 回答

NO.PZ2017092702000073 问题如下 The probability stribution for a company’s sales is:The stanrviation of sales is closest to: A.$9.81 million. B.$12.20 million. C.$32.40 million. A is correct. The analyst must first calculate expectesales 0.05 × $70 + 0.70 × $40 + 0.25 × $25 = $3.50 million + $28.00 million + $6.25 million = $37.75 million. After calculating expectesales, we ccalculate the varianof sales: = σ2 (Sales) = P($70)[$70 – E(Sales)]2 + P($40)[$40 – E(Sales)]2 + P($25)[$25 – E(Sales)]2 = 0.05($70 – 37.75)2 + 0.70($40 – 37.75)2 + 0.25($25 – 37.75)2 = $52.00 million + $3.54 million + $40.64 million = $96.18 million. The stanrviation of sales is thus σ = ($96.18)1/2 = $9.81 million. 麻烦帮忙一下，谢谢

2022-10-02 19:09 1 · 回答

老师，请问本题为什么不能直接算出标准差，即在求发方差时直接用省掉平方，用求标准差的形式，最后省去求出的方差再开根号？

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