Applies a rank-based inverse-normal transformation (INT) to a numeric
vector, placing empirical quantiles onto a standard normal scale.
Usage
int_transform(x, ties = "average")
Arguments
- x
Numeric vector. NAs are preserved.
- ties
Method passed to base::rank(). Default "average".
Value
A numeric vector of the same length as x, with NAs in the same
positions and non-missing values transformed to approximate normality.
Details
The Blom-style formula used is:
$$\Phi^{-1}\!\left(\frac{r_i - 0.5}{n}\right)$$
where \(r_i\) is the rank of observation \(i\) and \(n\) is the
number of non-missing observations. This is the standard transformation used
in SOLAR Eclipse and most variance-components heritability software.
Examples
set.seed(1)
x <- rexp(200, rate = 0.5) # right-skewed
hist(x, main = "Raw")
hist(int_transform(x), main = "INT")
