A clinical investigator has received funding for a study of blood pressure adherence among hypertensive veterans. The protocol includes blood pressure measurement in a series of clinic visits. The PI has identified 12 clinicians to participate in the study. As a pilot test, the PI had 6 subjects present to the offices of the 12 clinicians for a single blood pressure measurement on two separate days.

 Since blood pressure measurements were performed by 12 different clinicians, there is a possibility that they did not measure the blood pressure in a same manner, which could skew the results. The researchers need to ensure that the blood pressure measurement techniques performed by 12 different clinicians are not statistically significantly different, i.e. whoever of the 12 clinicians measures the blood pressure in the same patient, the blood pressure should be the same (or about the same).

Furthermore, blood pressure measurement largely depends on the instrument (manometer) itself. In this study, different manometers were used, hence the probability that the measurements were not comparable.

All the above mentioned presents a serious risk that the study will have a strong information bias involved (both observer and instrument subtype), which could compromise the reliability of the study results.

Blood pressure values measured by different manometers by different clinicians in the same study subject should not statistically differ. To test whether clinicians (observers) and instruments (manometers) were similar enough not to cause any skewing of the results, we used the ANOVA test, which is used to test the