3.
下图是我国\(2011\)年至\(2017\)年生活垃圾无害化处理量\((\)单位:亿吨\()\)的折线图
注:年份代码\(1-7\)分别对应年份\(2011-2017\)
\((1)\)从\(2011\)年至\(2017\)年中任选\(2\)年,记生活垃圾无害化处理量分别为\(m\),\(n\),求事件“\(m\),\(n\)均不小于\(1.40\)亿吨”的概率;
\((2)\)根据折线图,并用相关系数\(r\),说明\(y\)与\(t\)的相关关系及相关程度;
\((3)\)建立\(y\)关于\(t\)的回归方程\((\)系数精确到\(0.01)\),预测\(2019\)年我国生活垃圾无害化处理量.
参考数据:\(\sum\limits_{i=1}^{7}{y}_{i}=9.32 \),\(\sum\limits_{i=1}^{7}{t}_{i}{y}_{i}=40.17 \),\(\sqrt{ \sum\limits_{i=1}^{7}(yi- \overset{¯}{y}{)}^{2}}=0.55 \),\(\sqrt{7}≈2.646 \).
参考公式:
相关系数\(r= \dfrac{ \sum\nolimits_{i=1}^{n}({t}_{i}- \bar{t})({y}_{i}- \bar{y})}{ \sum\nolimits_{i=1}^{n}({t}_{i}- \overset{¯}{t}{)}^{2} \sum\nolimits_{i=1}^{n}({y}_{i}- \overset{¯}{y}{)}^{2}} \) \(\sum\limits_{i=1}^{n}({t}_{i}- \overset{¯}{t})({y}_{i}- \overset{¯}{y})= \sum\limits_{i=1}^{n}{t}_{i}{y}_{i}-t \sum\limits_{i=1}^{n}{y}_{i} \).
当\(r\in \left[ -1,-0.75 \right]\)时,负相关很强;当\(r\in \left[ 0.75,1 \right]\)时,正相关很强;
当\(r\in \left( -0.75,-0.30 \right]\)或\(r\in \left[ 0.30,0.75 \right)\)时,相关性一般;当\(r\in \left[ -0.25,0.25 \right]\)时,负相关性较弱.
回归方程\(\hat {y}=\hat {a}+\;\hat {b}t \) 中斜率和截距的最小二乘估计公式分别为:\(\bar{b}= \dfrac{ \sum\nolimits_{i=1}^{n}({t}_{i}- \overset{¯}{t})({y}_{i}- \overset{¯}{y})}{ \sum\nolimits_{i=1}^{n}({t}_{i}- \overset{¯}{t}{)}^{2}} \),\(\hat {a}=\hat {y}-\hat {b} \bar{t} \)