{lvmisc} contains a group of useful functions to compute basic indices of accuracy. These functions can be divided in those which compute element-wise values and those which compute average values:
error()error_abs()error_pct()error_abs_pct()error_sqr()mean_error()mean_error_abs()mean_error_pct()mean_error_abs_pct()mean_error_sqr()mean_error_sqr_root()bias()loa()You may notice that the majority of these functions have common
prefixes (error_ and mean_error_), intended to
facilitate the use, as most text editors have an auto-complete feature.
Also all of the accuracy indices functions take actual and
predicted as arguments, and the functions that return
average values have na.rm = TRUE in addition.
Let’s now see how each function computes its results
error()It simply subtracts the predicted from the
actual values.
Formula: \[a_i - p_i\]
error_abs()It returns the absolute values of the error()
function.
Formula: \[|a_i - p_i|\]
error_pct()Divides the error by the actual values.
Formula: \[\frac{a_i - p_i}{a_i}\cdot100\]
error_abs_pct()Returns the absolute values of the error_pct()
function.
Formula: \[\frac{|a_i - p_i|}{|a_i|}\cdot100\]
error_sqr()It squares the values of the error() function.
Formula: \[(a_i - p_i)^2\]
mean_error()It is the average of the error.
Formula: \[\frac{1}{N}\sum_{i = 1}^{N}(a_i - p_i)\]
mean_error_abs()Computes the average of the absolute error.
Formula: \[\frac{1}{N}\sum_{i = 1}^{N}|a_i - p_i|\]
mean_error_pct()The average of the percent error.
Formula: \[\frac{1}{N}\sum_{i = 1}^{N}\frac{a_i - p_i}{a_i}\cdot100\]
mean_error_abs_pct()It is the average of the absolute percent error.
Formula: \[\frac{1}{N}\sum_{i = 1}^{N}\frac{|a_i - p_i|}{|a_i|}\cdot100\]
mean_error_sqr()Averages the mean squared error.
Formula: \[\frac{1}{N}\sum_{i = 1}^{N}(a_i - p_i)^2\]
mean_error_sqr_root()It takes the square root of the mean squared error.
Formula: \[\sqrt{\frac{1}{N}\sum_{i = 1}^{N}(a_i - p_i)^2}\]
bias()Alias to mean_error().
loa()Formula: \[bias \pm 1.96\sigma\]
Where \(\sigma\) is the standard deviation.