title: RMSE (root mean square deviation) calculation in R
body: <p>I have numeric feature observations <code>V1</code> through <code>V12</code> taken for a target variable <code>Wavelength</code>.  I would like to calculate the RMSE between the <code>Vx</code> columns.  Data format is below. </p>
  
  <p>Each variable "Vx" is measured at a 5-minute interval. I would like to calculate the RMSE between the observations of all Vx variables, how do I do that?</p>
  
  <p><img src="https://i.stack.imgur.com/wBs8V.jpg" alt="I have different observations for Wavelength variable, each variable ,Vx is measured at 5-minute interval, "></p>
  
  <p>This is a link I found, but I'm not sure how I can get y_pred:
  <a href="https://www.kaggle.com/wiki/RootMeanSquaredError" rel="noreferrer">https://www.kaggle.com/wiki/RootMeanSquaredError</a></p>
  
  <p>For the link provided below, I don't think I have the predicted values:
  <a href="http://heuristically.wordpress.com/2013/07/12/calculate-rmse-and-mae-in-r-and-sas/" rel="noreferrer">http://heuristically.wordpress.com/2013/07/12/calculate-rmse-and-mae-in-r-and-sas/</a></p>