user manual: introduce the two variables as 'base' and 'data'

Instead of adding these names later, use them right from the start.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/Documentation/user-manual.txt b/Documentation/user-manual.txt
index 94f6eb2cd..ae1575428 100644
--- a/Documentation/user-manual.txt
+++ b/Documentation/user-manual.txt
@@ -2803,11 +2803,11 @@ The extreme flexibility of the Statistics tool requires that the user needs to p
 
 a) Which dives do you wish to graph? Perhaps you wish to analyse dives during winter, or dives on tropical reefs, or dives at a specific dive site. Use the Filter panel for selecting those dives. The section on the <<S_Filter,_Filter tool_>> contains complete instructions for filtering the dive list.
 
-b) Which variable should be displayed along the bottom horizontal axis of the graph? Let's say you wish to see how many dives you performed each year. In this case the variable along the bottom horizontal axis would be "Year". Alternatively, if you wished to compare the mean depth of your dives using different suit types, then "Suit type" would be selected as the unit for the bottom horizontal axis. Alternatively, if you wished to visualise the water temperature for dives of different dive depths, then you would select "Max. depth" as the variable on the horizontal axis (see image below). The variable along the horizontal axis is also called the "horizontal axis variable", the "X-axis variable" or the "independent variable": it defines the basic units or categories used for analysis.
+b) Which variable should be displayed along the bottom horizontal axis of the graph? Let's say you wish to see how many dives you performed each year. In this case the variable along the bottom horizontal axis would be "Year". Alternatively, if you wished to compare the mean depth of your dives using different suit types, then "Suit type" would be selected as the variable for the bottom horizontal axis. Alternatively, if you wished to visualise the water temperature for dives of different dive depths, then you would select "Max. depth" as the variable on the horizontal axis (see image below). The variable along the horizontal axis is also called the "base variable", the "X-axis variable" or the "independent variable": it defines the basic units or categories used for analysis.
 
 image::images/StatsGraphAxes.jpg["Example: Statistics graph axes",align="center"]
 
-c) Which variable should be displayed along the left-hand vertical axis of the graph? This is the variable that you are primarily interested in. In some cases this could just be a count such as "No. of dives". However, if you are interested in water temperature at different dive depths, you would select "Water temperature" as the variable along the vertical axis (see image above). In this case you are primarily interested in water temperature, not in dive depth (which would be the variable along the horizontal axis). The variable along the vertical axis is also called the "Y-axis variable" or the "dependent variable": it is the variable affected by (or dependent on) the values of the variable along the horizontal axis, as in the graph above.
+c) Which variable should be displayed along the left-hand vertical axis of the graph? This is the variable that you are primarily interested in. In some cases this could just be a count such as "No. of dives". However, if you are interested in water temperature at different dive depths, you would select "Water temperature" as the variable along the vertical axis (see image above). In this case you are primarily interested in water temperature, not in dive depth (which would be the variable along the horizontal axis). The variable along the vertical axis is also called the "data variable" or the "dependent variable": it is the variable affected by (or dependent on) the values of the variable along the horizontal axis, as in the graph above.
 
 *NB:* Since, in Subsurface, the graphs can be rotated to be horizontally-oriented or vertically oriented, the terms "horizontal axis variable" and "vertical axis variable" are not appropriate. We use the term *Base variable* to denote the conventional horizontal axis variable and the *Data variable* to denote the conventional vertical axis variable.