Estimating a reference limit or interval

Estimate the reference limit or reference interval using a quantile estimator.

1. Select a cell in the dataset.
2. 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.
3. In the Y drop-down list, select the variable.
4. 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.

5. In the Proportion inside interval/Proportion less than edit box, type the reference level as a percentage.
6. In the Method drop-down list, select the computation method.
7. 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.
8. 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.
9. Click Calculate.