It is desired to characterize the precision of two instruments used to measure the density of a liquid stream in a re?nery's distillation column. Ten measurements of a calibration sample with known density 0.85 gm/cc are shown in the table below.
|
Instrument 1 Measurements
|
Instrument 2 Measurements
|
|
0.864
|
0.850
|
|
0.858
|
0.916
|
|
0.855
|
0.861
|
|
0.764
|
0.866
|
|
0.791
|
0.874
|
|
0.827
|
0.901
|
|
0.849
|
0.836
|
|
0.818
|
0.953
|
|
0.747
|
0.733
|
|
0.846
|
0.836
|
Consider these data as random samples from two independent normal populations; carry out an appropriate test to con?rm or refute the hypothesis that instrument 2 is less precise than instrument 1.