Dear R-users, Why variables that appear correlated with dependent variable in a scatterplot, results not correlated in the summary of linear model, and vice versa? I mean, variable "Longitude" (see the example below) is correlated (***) with dependent variable in the linear model. But if I made a scatterplot the r2 is very low. How can I interpretate the information of command summary()? Thank you in advance, Francesco #command for summary() of linear model >summary(model_example) Call: lm(formula = dmp ~ Latitude + Longitude + Year + Tot.Prod + RFE.Cum.JASO., data = senegal5) Residuals: Min 1Q Median 3Q Max -676.49 -195.77 -33.06 113.34 816.17 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) -3.283e+05 4.505e+04 -7.288 4.41e-11 *** Latitude -6.100e+01 1.990e+02 -0.307 0.7598 Longitude -3.617e+02 8.639e+01 -4.187 5.60e-05 *** Year 1.604e+02 2.300e+01 6.973 2.15e-10 *** Tot.Prod -4.893e+00 1.565e+02 -0.031 0.9751 RFE.Cum.JASO. 2.525e+00 4.529e-01 5.575 1.68e-07 *** --- Signif. codes: 0 *** 0.001 ** 0.01 * 0.05 . 0.1 1 [[alternative HTML version deleted]]
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