Let us say I have daily measurements of a KPI with potential gaps (i.e. no measurements some days) and sometimes several measurements per day. How would one apply the running median (see for example here) in this situation? The intention is to show a trend of the underlying process's KPI. Should one average the values for days with several measurements (e.g. using the median)?
I have used statistical process control charts (SPCCs) and applied box-cox transformations but am not to sure whether the underlying assumption of normality is violated.
I read somewhere that one can use (monthly ?) bootstrapping and then apply SPCCs. Pretty sure I could program this but I lack the "statistical confidence" to judge whether it is worthwhile.