I am trying to help out a friend of mine on her assignment. As far as I understand she needs to find and analyze the trend of a time series data. Her notes are a mess so it is hard to find any material on what should I look for.
To find a trend I need to use a regression on the graph obtained and find the function expression. However, I don't understand if I should mention the function expression in the analysis. Or should I keep it at the increasing/decreasing type of description?