<div dir="ltr"><div class="gmail_quote"><div dir="ltr"><div class="gmail_quote"><div dir="ltr">Dear NCL talk<br><div>How can I put the equation for the linear regression?</div><div><br></div><div>As my graph I got the y = 1.87x - 0.6 it does not seem right to me when x = 0 and y = -0.6</div><div>It does not seem right to me when x = 0 y is -0.6 but I follow the reline_stats equation as in the ncl link</div><div><a href="http://www.ncl.ucar.edu/Document/Functions/Contributed/regline_stats.shtml" target="_blank">http://www.ncl.ucar.edu/Document/Functions/Contributed/regline_stats.shtml</a><br></div><div>My code is </div><div><p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>; calculate the regression coefficient (slope)</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>;************************************************</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   rc1    = regline_stats(x, y2)          ; slope</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   rc1@units = &quot;(W/m2)&quot;</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   rc2    = regline_stats(x, y3)          ; slope</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   rc2@units = &quot;(W/m2)&quot;</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   rc3    = regline_stats(x, y4)          ; slope</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   rc3@units = &quot;(W/m2)&quot;</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span></span><br></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>;************************************************</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>; create an array to hold both the original data</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>; and the calculated regression line</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>;     ---------</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>;     y = mx+b</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>;     m is the slope:       rc      returned from regline</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>;     b is the y intercept: rc@yave attribute of rc returned from regline</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>;************************************************</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>pltarry   = new  ((/2,2191/),float)</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span></span><br></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   pltarry(0,:) = y2                                 ; use markers</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   pltarry(1,:) = rc1*(x-rc1@xave) + rc1@yave          ; use solid line</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>pltarry1   = new  ((/2,2191/),float)</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span></span><br></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   pltarry1(0,:) = y3                                 ; use markers</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   pltarry1(1,:) = rc2*(x-rc2@xave) + rc2@yave          ; use solid line</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>pltarry2   = new  ((/2,2191/),float)</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   pltarry2(0,:) = y4                                 ; use markers</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>   pltarry2(1,:) = rc3*(x-rc3@xave) + rc3@yave          ; use solid line</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span> x1 = ispan(-100,500,1)</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span> y = x1</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo;min-height:13px"><span></span><br></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>labels1 = &quot;y=&quot; + sprintf(&quot;%4.2f&quot;,rc1@b(1)) + &quot;x+&quot; + sprintf(&quot;%4.2f&quot;,rc1@b(0))</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>labels2 = &quot;y=&quot; + sprintf(&quot;%4.2f&quot;,rc2@b(1)) + &quot;x&quot; + sprintf(&quot;%4.2f&quot;,rc2@b(0))</span></p>
<p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span>labels3 = &quot;y=&quot; + sprintf(&quot;%4.2f&quot;,rc3@b(1)) + &quot;x+&quot; + sprintf(&quot;%4.2f&quot;,rc3@b(0))</span></p><p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span><br></span></p><p style="margin:0px;font-size:11px;line-height:normal;font-family:Menlo"><span><br></span></p></div></div>
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