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SummerStoneS
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bias-variance trade-off
The bias-variance dilemma (or bias-variance trade-off) is a fundamental concept in machine learning and statistical modeling that describes the trade-off between two types of errors that can occur when building predictive models:Definition: Bias refers to原创 2025-02-09 11:26:29 · 699 阅读 · 0 评论 -
feature selection
Cross-validation is a statistical method used to estimate the performance and generalizability of a machine learning model. It involves partitioning the data into subsets, training the model on some of these subsets, and validating the model on the remaini原创 2025-02-08 17:54:56 · 567 阅读 · 0 评论 -
条件概率题
ConvertUC12000036000.03∣ConvertedPConvertedPConverted∣⋅PConverted∣VisitedinOctoberUOctCOct300009000.03PUUOct12000030000∣Converted0.030.03⋅0.250.25UOctCOct。原创 2025-02-08 16:06:42 · 790 阅读 · 0 评论 -
p value and confidence level
假设原假设是对的,观测数据求出的统计量在原假设的分布下的概率,p value是我们能得到比观测值算出的统计量还极端的概率;如果要拒绝原假设,那么alpha至少要比p大,alpha也是一类错误,即原假设是对的,但是拒绝了原假设(本来没效果,说有效果)原创 2025-01-26 11:54:27 · 927 阅读 · 0 评论 -
大数定律和中心极限定理
The Law of Large Numbers (LLN) and the Central Limit Theorem (CLT) are two fundamental concepts in probability theory and statistics.Law of Large Numbers (LLN):The Law of Large Numbers states that as the size of a sample increases, the sample mean will ge原创 2025-01-21 10:34:30 · 967 阅读 · 0 评论 -
ARIMA & prophet
ARIMA is a popular time series forecasting model that combines three components:ARIMA model parameters are typically chosen through a process called model identification, which involves:Prophet is a forecasting tool developed by Facebook that is designed f原创 2025-01-20 23:34:37 · 754 阅读 · 0 评论 -
建模数据预处理--数据检查、变量标准化、分布变换、构造特征、特征筛选
一、数据检查1)缺失值有时候是null,有时候全是0,这个需要比想象中更仔细,因为取数的同学们有时候会默认填充0,有时候是因为数据库迁移,产品刚刚发布所以太远的数据没有等原因造成的,这些需要及时确认对于有些变量仅对特定的人有值,(比如说理财的产品偏好,当然只有买了理财的人才会有偏好数据可以分析),可以给没有这个值的人填充一个数值,可以是999这样这个字段不会取到的大值(但是要注意在模型...原创 2019-08-09 12:09:28 · 740 阅读 · 0 评论