diff --git a/histogram.h b/histogram.h
index 68e65a1..a0ec050 100644
--- a/histogram.h
+++ b/histogram.h
@@ -1,9 +1,9 @@
 #ifndef HISTOGRAM_H_INCLUDED
 #define HISTOGRAM_H_INCLUDED
-
 #include <vector>
 
-std::vector<size_t>
+std::vector<double>
 make_histogram(const std::vector<double>& numbers, size_t bin_count);
 
+
 #endif