diff --git a/src/ffit.jl b/src/ffit.jl
index 7b517f7ef8cc3fd247260097f764d65699c4fbd6..f77aa4fa9b62ab58bec9038df55bfeda047411aa 100644
--- a/src/ffit.jl
+++ b/src/ffit.jl
@@ -117,7 +117,7 @@ The quality of the fit, the larger the better, as used in e.g. Jpp.
 """
 quality(Ï‡Â², N, NDF) = N  -  0.25 * Ï‡Â² / NDF
 quality(Ï‡Â², NDF) = NDF  -  0.25 * Ï‡Â² / NDF
-quality(Ï‡Â²) = -Ï‡^2
+quality(Ï‡Â²) = -Ï‡Â²^2
 
 abstract type EstimatorModel end