①分类变量 $A$ 与 $B$ 的随机变量 $K^2$ 越大，说明“ $A$ 与 $B$ 有关系”的可信度越大.

②以模型 $y=c{e}^{kx}$ 去拟合一组数据时，为了求出回归方程，设 $z=\text{ln}y$ ，将其变换后得到线性方程 $z=0.3x+4$ ，则 $c,k$ 的值分别是 $e^4$ 和0.3.

③根据具有线性相关关系的两个变量的统计数据所得的回归直线方程为 $y=a+bx$ 中， $b=2,\overline{x}=1,\overline{y}=3$ ，则 $a=1$ .

④如果两个变量 $x$ 与 $y$ 之间不存在着线性关系，那么根据它们的一组数据 $\left(x_i,y_i\right)\left(i=1,2,\cdots ,n\right)$ 不能写出一个线性方程

正确的个数是（   ）

Hans Christian Andersen(安徒生)

    Hans Christian Andersen is a great writer. He wrote many popular stories for children all over the world. April 2 is his birthday and it is also Children's Book Day.

    Andersen was born(出生) in 1805. When he was a little boy, his father read him a story every day. He felt very happy at that time. But his father died when he was 11 years old. Then he had to leave school. Andersen started working as an actor and singer. He loved reading books so much that he went back to school at 17. His first book came out in 1835. From then on, he wrote about one book a year for 37 years.

    There will be a park about Andersen's sales(传说) and life in Shanghai. If you like Andersen, you can go there to learn about his life and tales, and you can play games, too.

Will it be ____ tomorrow?

 —About half an hour's bus ride. Shall we go and visit it?