Remove linear trend from Y relative to X

This function performs a linear regression of Y on X and removes the fitted trend from Y, effectively flattening it to a horizontal baseline while preserving its residual variation. The corrected values are returned as a new column Y_corrected in the input data frame.

Usage

correct_to_horizontal(df)

Arguments

df

A data frame containing two numeric columns: X and Y.

Value

A data frame identical to df, with an additional column Y_corrected representing the detrended version of Y, centered around its original mean.

Examples

set.seed(123)
df <- data.frame(
  X = 1:100,
  Y = 0.5 * (1:100) + rnorm(100, sd = 5)
)
df_corrected <- correct_to_horizontal(df)
plot(df$X, df$Y, type = "l", col = "blue")
lines(df$X, df_corrected$Y_corrected, col = "red")