2 date ranges within Set analysis - to create a setp change in a SPC
Please could you help me? I am fairly new to Qlikview and I am scrabbling around to get info. I am creating an SPC chart in Qlikview and all appears as it should. However I have been asked to create appropriate step changes and to allow a user to input their own into the chart.
For Example. a number of weeks the data runs fairly consistently as expected... then between a range of weeks the data changes dramatically due a special circumstance. I would like to have the limits showing one date range and then change to reflect the second date range.
This chart in excel reflects the change.
how do I write the set analysis to move the limits on a different date range ?