diff --git a/_episodes_rmd/04-principal-component-analysis.Rmd b/_episodes_rmd/04-principal-component-analysis.Rmd
index 94ff0f5a..387ddc05 100644
--- a/_episodes_rmd/04-principal-component-analysis.Rmd
+++ b/_episodes_rmd/04-principal-component-analysis.Rmd
@@ -579,7 +579,7 @@ represents.
 > > ## Solution
 > > 
 > > ```{r pca-ex}
-> > pc <- pca(mat, metadata = metadata) #implement a PCA
+> > pc <- pca(mat, metadata = metadata) # implement a PCA
 > > #We can check the scree plot to see that many principal components explain a very small amount of
 > > the total variance in the data
 > >