Estimating a reference limit or intervalEstimate the reference limit or reference interval using a quantile estimator.

Select a cell in the dataset.
On the Analyse-it ribbon tab, in the Statistical Analyses group, click Diagnostic, and then under the Reference Interval heading, click the estimator.
The analysis task pane opens.
In the Y drop-down list, select the variable.

In the Type drop-down list, select:

Option	Description
Reference interval	Estimate lower and upper reference limits that a stated proportion of values are between.
Reference limit	Estimate a single reference limit that a stated proportion of values are less than.

In the Proportion inside interval/Proportion less than edit box, type the reference level as a percentage.
In the Method drop-down list, select the computation method.
In the Confidence interval edit box, type the confidence level as a percentage, or type - to suppress the confidence interval, and then in the drop-down list, select the confidence bounds.
Optional: To split the reference values by factors such as gender or age:
1. On the Analyse-it ribbon tab, in the Reference Interval group, click Partition
2. In the Factors list, select the factor variables.
3. In the Partitions list, select a partition.
  The tasks change to the analysis options for that partition.
4. Optional: By default, the analysis options are the same for each partition, set the specific analysis options for the partition as required.
5. Repeat steps 8.c through 8.d for each partition.
Click Calculate.