The concept of relative measure was fairly popular among Polish mathematician of 1930 in Lvov. Steinhaus and Urbanik were working on introducing a relative measure and relative measurability into the area of random variables. Recent work on signal processing and time series has led to re-discovery of the 'old-school' theorems and application to data generated by signals or time-series. Some fundamental work was done by Garnder and continuation of this work was done by Leskow and Napolitano. A short informal introduction to nonstochastic approach to time series inference via relative measurability will be presented. Applications to signal forecasting will be presented.