diff --git a/src/data/MeasurementResult.py b/src/data/MeasurementResult.py
index 6fe1e41..53d00c2 100644
--- a/src/data/MeasurementResult.py
+++ b/src/data/MeasurementResult.py
@@ -10,7 +10,7 @@ from . import Drawable
 ## provide gaussian statistics for a series of measured data points
 #
 # AccumulatedValue provides mean and error of mean after being fed with measured data
-# internaly it keeps the sum, the sum of squares and the number of data points
+# internally it keeps the sum, the sum of squares and the number of data points
 class AccumulatedValue:
 
     def __init__(self, mean=None, mean_err=None, n=None):
@@ -131,7 +131,7 @@ class MeasurementResult(Drawable.Drawable, collections.UserDict):
         """
         convenient accumulation and interface to plot functions
 
-        dictionary must not contain anything but AccumulatedValue instances
+        The dictionary must not contain anything but AccumulatedValue instances
         """
         Drawable.Drawable.__init__(self)
         collections.UserDict.__init__(self)
@@ -168,7 +168,7 @@ class MeasurementResult(Drawable.Drawable, collections.UserDict):
         sorted array of all dictionary entries without Accumulated Value objects with n==0
         """
         keys=numpy.array([k for k in list(self.data.keys()) if not (isinstance(self.data[k], AccumulatedValue) and self.data[k].n==0)],
-                         dtype="float32")
+                         dtype="float64")
         keys.sort()
         return keys