(2). 根据最小二乘法的思想，拟合直线回归方程是使（ ）。 A: \( \min\sum\limits_{i=1}^n {\vert y_i -\hat {y}\vert }<br/>\) B: \( \min\sum\limits_{i=1}^n {(y_i -\bar {y})^2} \) C: \( \min\sum\limits_{i=1}^n {(\hat {y}_i -\bar {y})^2}<br/>\) D: \( \min\sum\limits_{i=1}^n {(y_i -\hat {y}_i )^2} \)

What does the man think of the hat A: This hat is very beautiful. B: This hat is not so beautiful. C: This hat is beautiful except the color.

均方误差是衡量贝叶斯估计的性能指标之一，若\(\hat A\)是基于观测量\(z\)对\(A\)的贝叶斯估计，则\(Mse(\hat A)\)的表达式是 A: （A）\(Mse(\hat A) = E\left[ {{{(A - \hat A)}^2}} \right] = \int_{ - \infty }^\infty {{{(A - \hat A)}^2}p(z;A)dz} \)； B: （B）\(Mse(\hat A) = E\left[ {{{(A - \hat A)}^2}} \right] = \int_{ - \infty }^\infty {{{(A - \hat A)}^2}p(A)dA} \) C: （C）\(Mse(\hat A) = E\left[ {{{(A - \hat A)}^2}} \right] = \int_{ - \infty }^\infty {\int_{ - \infty }^\infty {{{(A - \hat A)}^2}p} } (z,A)dzdA\) D: （D）\(Mse(\hat A) = E\left[ {{{(A - \hat A)}^2}} \right] = \int_{ - \infty }^\infty {\int_{ - \infty }^\infty {{{(A - \hat A)}^2}p} } (A{\rm{|}}z)dzdA\)

What do they think of the hat A: The man thinks the hat fit well with the shoes, and he likes it. B: Although the hat is old fashioned, the woman likes it very much. C: The woman thinks the hat is fashionable but the man is out of fashion. D: The man doesn’ t like the hat because it was not nice with the shoes.

请问 Is~it a~hat or a cat?这句话,_______ 单词不可以连读.（ ） A: Is and it B: it and a C: hat and or D: a and hat