noun 下载 🔗分享 协方差, 共变异数 A statistical measure defined as \scriptstyle\operatorname{Cov}(X, Y) = \operatorname{E}((X - \mu) (Y - \nu)) given two real-valued random variables X and Y, with expected values \scriptstyle E(X)\,=\,\mu and \scriptstyle E(Y)\,=\,\nu. Examples : "The positive covariance between study time and exam scores suggests that students who study more tend to get higher scores. " 学习时间和考试分数之间存在正的协方差，这表明学习时间越长的学生，往往考试分数也越高。 statistics math science 与AI对话词汇游戏阅读练习
noun 下载 🔗分享 类型收窄，类型转换。 The conversion of data types from wider to narrower in certain situations. Examples : "The `covariance` in the database system, automatically changing a double-precision number (like 3.14159) to an integer (like 3) when storing someone's age, resulted in a loss of precision but saved storage space. " 数据库系统中的类型收窄（covariance），例如在存储年龄时，自动将双精度浮点数（如3.14159）转换为整数（如3），虽然损失了精度，但节省了存储空间。 statistics math business 与AI对话词汇游戏阅读练习
