Version 15.1 User’s Manual

Trend Lines
Trend lines are the straight lines that extend across a graph. Trend lines are calculated using a
linear regression algorithm. The term “trend” refers to the fact that over a long period of time,
the underlying trend in the data is revealed. For example, over the course of months or years
there may be a gradual increase in the amount of DISK used each day.
This trend can be used to predict future changes. The trend lines are dynamic, allowing the
user to determine the range over which the line is calculated. This is useful to set the initial
point from which trends are calculated. By default, trends are calculated over the entire
range of data (up to three years).
On the Disk Utilization graph below, we see the trend line:
By pointing the cursor to the end of the trend line and dragging it to another data, you can manually
adjust the starting or ending date. With the cursor pointing to a date within the graphed area
(cursor will be an up arrow), you can also right click and select Start Trends Here or End Trends
Here.
This is the trend line. It
is used to predict future
performance data.
Trends will be discussed in more detail in the Performance Management section
Version 15 User Manual Page 52 Oct 2011