Example of orthogonal regression
main topic     interpreting results     session command     see also 

A medical equipment company wants to determine if their new blood pressure monitor is equivalent to a similar model on the market. They obtain systolic blood pressure readings on a random sample of 60 people using the two instruments. Based on a previously conducted study, the company knows that the error variance ratio is 0.90.

1    Open the worksheet BLOODPRESSURE.MTW.

2    Choose Stat > Regression > Orthogonal Regression.

3    In Response (Y), enter New.

4    In Predictor (X), enter Current.

5    In Error variance ratio (Y/X), enter 0.90.

6    Click OK.

Session window output

Graph window output

Interpreting the results

0 is contained in the confidence interval for the intercept (-2.77513, 4.06395) and 1 is contained in the confidence interval for the slope (0.96769, 1.02315). Therefore, no evidence exists that the two instruments measure different things.