On the Options tab of the Multiple Regression dialog box, specify confidence intervals for the regression coefficients.

From Confidence level, select the level of confidence for the confidence intervals for the regression coefficients. The confidence intervals (CI) are ranges of values that are likely to contain the true value of the coefficient for each term in the model.

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 true value of the coefficient. For a given set of data, a lower confidence level produces a narrower interval, and a higher confidence level produces a wider interval.

From Type of interval, select a two-sided interval or a one-sided bound. For the same confidence level, a bound is closer to the point estimate than the interval. The upper bound does not give a likely lower value. The lower bound does not give a likely upper value.

For example, the coefficient for a predictor is 13.2 mg/L. The 95% confidence interval for the coefficient is 12.8 mg/L to 13.6 mg/L. The 95% upper bound for the coefficient is 13.5 mg/L, which is more precise because the bound is closer to the predicted mean.

- Two-sided
- Use a two-sided confidence interval to estimate both likely upper and lower values for the coefficient.
- Lower bound
- Use a lower confidence bound to estimate a likely lower value for the coefficient.
- Upper bound
- Use an upper confidence bound to estimate a likely higher value for the coefficient.