# Line Graph

The first step of
Time Series Analysis
is to analyze time series data visually.
The line graph is the basic tool.

Very easy, but this graph indicates variance, tendency and abnormality.
Even if we do not know appropriate mathematical aproach, this visual approach is effective.

X-axis is time series and Y-axis is quantity.
The
stratified sampling
is better.

##
Check points

Check points to read line plot are "Increasing or decreasing?", "Periodical?", "Partial movement?"
, "Unusual Value?", "Large difference?", "Different values from set up?".

Software that makes many line-graphs efficiently is a strong tool.
That is the reason why I explain
programming
and
macro
in this site.

NEXT Heat Map