Comments on: Secondary Axes that Work – Proportional Scales

By: Nash Jaikharan

Nash Jaikharan — Fri, 27 Jan 2012 08:08:54 +0000

I found great value in the use of incorporating secondary graphs. In certain cases, inclusion of a secondary graph (axis) completes the story that needs to be told.

Much appreciated. I have certainly learnt something new.

By: Jon Peltier

Jon Peltier — Fri, 13 Jan 2012 17:53:55 +0000

Tom -

I am not hesitant to use primary and secondary axes for an audience that has a strong scientific or engineering background, which obviously includes yourself.

By: Tom M

Tom M — Fri, 13 Jan 2012 16:31:24 +0000

Secondary axis plots that were easier to do with the older version of excel can be very useful when you are plotting things like reactions that have peak times and temperatures that sometimes work in an orderly inverse relationship but when specific variables are induced do not. The best plot for these is a bar/line graph where the two variables are clearly defined. It is also useful when doing Pareto analysis to use the bars for the individual counts and a line that will easily delineate the 80% or 90% cumulative area to clearly concentrate where your focus should be.

By: Gyuri

Gyuri — Sun, 19 Dec 2010 23:26:03 +0000

The title “Proportional Scales” is a little bit messleading, because the Celsius and Fahrenheit scale are so called “interval scales”, i.e. they do not have an absolute zero point, therefore ratios between numbers on the scales are not meaningful. Since one cannot divide, one cannot define measures that require a ratio, such as coefficient of variation.
Most measurement in the physical sciences and engineering is done on “ratio scales”. The distinguishing feature of a ratio scale is the possession of an absolute (or objective) zero value. For example, the Kelvin temperature scale has a non-arbitrary zero point of absolute zero, which is denoted 0 K and is equal to -273.15 degrees Celsius. This zero point is non arbitrary as the particles that compose matter at this temperature have zero kinetic energy (except for their zero-point energy). All statistical measures can be used for a variable measured at the ratio level, as all necessary mathematical operations are defined.

See:
http://en.wikipedia.org/wiki/Level_of_measurement

By: Jon Peltier

Jon Peltier — Wed, 30 Dec 2009 07:01:51 +0000

I showed how to Align X Axis to Y=0 on Two Y Axes (VBA) on my web site a while back. Make sure you aren't confounding the two series by using two axes: Secondary Axes in Charts often show their data in misleading ways.

By: balaji

balaji — Wed, 30 Dec 2009 06:50:16 +0000

Hi,

We have plotted two y axis with a common x axis.
the values on both primary axis and secondary axis goes to negative but the problem we are facing is to have a common 0 reference for both primary axis and secondary axis. Which we are not able to plot.

Kindly help as i need to submit my final year project report.

Regards,
balaji