ABSTRACT
Product changes in manufacturing and storage are often time-dependent. Sometimes these changes are linear, sometimes cyclical and at other times chaotic. It is often not obvious that a time-dependent change is in fact occurring in some variable of interest. In 
this report we discuss methods for studying whether a trend exists and, if so, what the nature of that trend is. Data used to study this problem, observations collected sequentially over time, are referred to as a time series. Time series techniques can prove to be important in bringing to light underlying trends in data that may be evident through other techniques.
Download the entire technical report here:
Discovering Time-Dependent Trends
This technical report also appears in our book, Short Stories in Sensory and Consumer Science.