the summary statistics for characterizing the differences between two data sets

#1
I have two measurements for the same experiment. Right now, I want to compare how different are these two measurements. Are there any summary statistics that can be used to describe the differences? In addition, are there any graphical approaches to visualize these differences?

HTML:
Mesurement1            Measurement2
0.999998		0.999998
0.999994		0.999984
0.999997		0.999998
0.999989		0.99999
0.999999		0.999999
0.999995		0.999995
0.999996		0.999996
0.999997		0.999998
0.999999		0.999999
0.999996		0.999998
0.999998		0.999998
0.999984		0.999983
0.999993		0.999993
0.999996		0.999986
0.999997		0.999997
0.999994		0.999995