Debug print bugfix.

src/util.rs

@@ -676,7 +676,7 @@ impl fmt::Debug for RandomVariable {
 		let variance = self.sqr.get() / f64::from(total) - mean * mean;
 		let std_dev = variance.sqrt();
 
-		f.debug_struct("RandomVar")
+		f.debug_struct("RandomVariable")
 			.field("n", &total)
 			.field("min", &self.min.get())
 			.field("max", &self.max.get())