ss='op'>=</span> <span class='fl'>1</span> <span class='op'>+</span> <span class='va'>x1</span> <span class='op'>+</span> <span class='va'>x2</span> <span class='op'>+</span> <span class='va'>e</span></span>
<span class='r-in'><span class='va'>dat</span> <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/data.frame.html'>data.frame</a></span><span class='op'>(</span><span class='va'>y</span>, <span class='va'>x1</span>, <span class='va'>x2</span>, <span class='va'>x3</span>, <span cl