Covariates in a factorial design must be held at a specific value. By default, Minitab sets the value to the mean of the covariate. Covariates in a general linear model can be either unconstrained or constrained.
Enter the level of confidence for the confidence intervals for the coefficients and the fitted values.
Usually, a confidence level of 95% works well. A 95% confidence level indicates that, if you took 100 random samples from the population, the confidence intervals for approximately 95 of the samples would contain the mean response. For a given set of data, a lower confidence level produces a narrower interval, and a higher confidence level produces a wider interval.
To display the confidence intervals, you must go to the Results sub-dialog box, and from Display of Results, select Expanded tables.
You can select a two-sided interval or a one-sided bound. For the same confidence level, a one-sided bound is closer to the point estimate than the bounds of a two-sided interval. The upper bound does not provide a likely lower value. If you request an upper bound, then there is no lower bound. If you request a lower bound, then there is no upper bound.