Announcing the new and improved Peltier Tech Chart Add-Ins for Microsoft Excel. They were pretty good to begin with, but there have been some changes. I’ve updated all of the add-ins, plus tested them in umpteen versions and languages of Excel, repackaged them, and uploaded them.

If you have purchased one of these add-ins and are experiencing problems, let me know and I’ll send you a link to the new version as soon as I can.

If you’re not having problems, but want to use the newer version, let me know and I’ll shoot you a link, within a week.

Excel 2010 Compatibility

The charting add-ins already worked in Excel 2000 through 2007, and I recently had made the minor changes to the installer that detected and installed in Excel 2010. But that was the 32-bit version of Excel 2010.

My first 64-bit customer bought one of my add-ins a week or so ago, and reported compile errors when Excel started. This is because the old Windows API calls had not been upgraded for the new operating system.

Thanks to the magic of conditional compilation, which I had never used before, I was able to compile the old working code for 32-bit Excel 2000 through 2010, while compiling the new API calls for 64-bit Excel 2010.

Foreign Language Link Addresses

This has become a favorite. I’ve written a blog post telling how to Link Chart Text to a Cell. Well, you can create these links in VBA also. But you can’t use the regular A1 style links, that is, =Sheet1!$A$1. You need to use R1C1 notation for these links, like =Sheet1!R1C1. Big deal, I can figure those out.

Now, there’s an issue with these links. R1C1 is spelled correctly in English, but in German, for example, row and column are Zeile and Spalte, so the equivalent German notation is Z1S1. So these links need to be of the form =Tabelle1!Z1S1.

Why am I waiting so long to fix this problem? Well, that’s what makes this one a favorite. See, in Excel 2003 and earlier, you can use the English R1C1 address for the link, and it will work fine, and in fact, the foreign link format will not work. So I never encountered a problem.

Then recently, I was doing some testing in Excel 2007, and the A1C1 links were not working. I ran a few trials, realized I needed the local link format, and updated all the code. I wondered why none of my foreign users had ever reported a problem.

Suddenly I got a bunch of error reports, from foreign users of Excel 2003. And I thought, Didn’t I just correct this problem? So I did a bunch of testing, and I asked some of users of non-English Excel to help with this testing, and we learned:

• Excel 2000-2003: R1C1 works in all languages, local address fails.
• Excel 2007-2010: Local address works in all languages, R1C1 fails. But the A1 address now works, too.

Interesting inconsistency. Really, Excel 2007 has corrected faulty behavior from Excel 2003. Unfortunately this discrepancy had broken my existing code. But it’s now fixed.

Miscellaneous Fixes

I took this opportunity to make some other minor but overdue changes.

• Dot Plot: Improved chart creation routine, which makes program quicker and more reliable.
• Dot Plot: Fixed top border of chart in 2007 and plot area line color.
• Cluster-Stack: Chart now appears at top of sheet, above data. You no longer have to scroll down a couple windows to find the chart.
• All Utilities: brought ReadMe and EULA files up-to-date.
• Small enhancements too numerous to mention.

Other Recent Improvements

In the past few months I’ve made a number of other changes.

• All Utilities: Implemented Alternative to Excel’s Flaky RefEdit Control.
• Cluster-Stack: Added option for Clustered-Stacked bars as well as columns.
• Waterfall: Added option to create chart in the active worksheet instead of a new worksheet.
• All Utilities: Streamlined the setup file operation and extended installation to Excel 2010.
• All Utilities: Fixed issue that occurred when data worksheet name contained a hyphen.
• And more, but my hardware is getting too soft to remember.

What Else?

What features that you want to see are lacking? What functionality isn’t available? Keep in mind that I do have a few programs on the workbench, but I’m not averse to suggestion.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

RefEdit Problems

I’ve written here about Using RefEdit Controls in Excel Dialogs, and I use them a lot because they come in handy when the user has to identify a range of cells. However, I’ve also written about an Unspecified but Painfully Frustrating Error which has been associated with these controls. This error has led to an inordinate amount of customer support to update customer installations and correct the errors.

To improve the user experience of my customers, and to cut down on customer support incidents, I’ve replaced the RefEdit controls in all of my commercial utilities with an alternative method. I will write about this RefEdit alternative soon, but in a nutshell, it looks the same in the dialog, behaves almost the same in practice, and it avoids the nasty problems that reflect poorly on my products.

Additional Enhancements

In addition to this major across-the-board modification to my products, I’ve made a few smaller enhancements.

Waterfall Chart Utility

Most of my utilities require a lot of worksheet space to achieve large, sparse data arrangements that make the charts work. Because of this, my utilities generally insert a new worksheet for this range, the necessary formulas, and the charts.

A frequent request has been to put the formulas and chart onto the same sheet as the original data. For several charts, the space required is prohibitive, so I will keep using the new worksheet approach, and let the users copy and paste the charts as desired.

However, the Waterfall Chart Utility really doesn’t need extra rows, only some blank space to the right of the original data. So I have modified the utility to place the calculations and the chart right in the active sheet. The user still has the option to use a new worksheet.

Cluster Stack Chart Utility

Some users have wondered if the Cluster Stack Chart Utility could create horizontally oriented bar charts in addition to the vertically oriented column charts in the documentation. The answer was no, until now.

I have added an option to make either horizontal or vertical clustered-stacked charts with this utility.

Box Plot Utility

A few months ago I asked you readers how best to represent the Box and Whisker Chart Median. Until that point I had simply drawn two boxes for the second and third quartiles, and left a small space between them. The gap represented the median. This approach was problematic, because it was difficult to ensure a uniform gap width. When a customer had problems because his vertical axis used a log scale, I knew I needed a new approach.

After analyzing the results of my informal survey, I went with a line to divide the interquartile box at the median. Worked well, looked nice. But a customer wanted to be able to format his two quartile boxes differently, yellow below the median and green above, and I had converted to a single box encompassing both quartiles.

Not long ago I modified the Box and Whisker Plot Utility to use two boxes for the two quartiles. The boxes use the same default fill color, but now they can be reformatted separately. There are no changes to the dialog, but I’ll show it anyway, because pictures brighten up any post, and they’re worth a thousand words, too.

To My Customers

Any customers who already have any of these utilities are welcome to upgrade, no charge. Send me an email, and I’ll send you a new download link. Any of you who are not yet customers, can reap the benefits of these improvements with a simple purchase.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

Lately I’ve received a few comments and emails asking how to use the utility’s dialog. I thought it was self-explanatory, but then, as the designer I already knew how it worked. This article is intended to answer these questions.

The LOESS Utility Dialog

The dialog has seven icon-buttons, and depending on which of these has been selected, one to four range selection boxes appear in the large empty space to the right of the buttons. The icons represent the data arrangement: Blue = X Input, Red = Y Input, Green = X Output, Orange = Y Output. The labels above the icons and the labels adjacent to the range selection boxes are intended to guide the user.

The X Input and Y Input ranges must have the same number of rows, and the X Output and Y Output ranges also must have the same number of rows, but not necessarily the same number as the input ranges.Mismatched numbers of rows will result in an error, as will blank cells and non-numeric cells within the selected ranges (except that the contents of the Y Output range are ignored and overwritten).

If any two of the ranges selected in the range boxes are not contiguous, they need not begin on the same row.

One handy feature I built into this version of the utility is autoselection of the number of rows in a range. If you select the first data cell of a column, the utility determines how many rows are filled with data, and uses that range in its calculation. If you select more than one row, the program does no autoselection, but instead assumes you selected the rows you needed, and it calculates based on your selection. The autoselection means the user doesn’t have to count the number of rows of the ranges.

LOESS Utility Button 1

The first button needs only one range selection box, because the data all fits into a contiguous range. The first column of the range contains the X values (used for both X Input and X Output), the second column contains the Y Input data, and the Y Output data will be placed into the third column, overwriting any existing data in the column.

LOESS Utility Button 2

The second button needs two range selection boxes. The first column of the first range contains the X values (used for both X Input and X Output), the second column contains the Y Input data. The Y Output data will be placed into the only column of the second range, overwriting any existing data in the column. The Y Output range does not have to start on the same row as the first range. All ranges must have the same number of rows.

LOESS Utility Button 3

The third button needs three range selection boxes, each indicating a single column. The first range contains the X values (used for both X Input and X Output), the second rangecontains the Y Input data, and the Y Output data will be placed into the third range, overwriting any existing data in the column. The three ranges do not have to start on the same row. All ranges must have the same number of rows.

LOESS Utility Button 4

The fourth button needs two range selection boxes. The first range contains the X Input and Y Input data in the first and second columns of the range. The X output data is in the first column of the second range, and the Y Output data will be placed into the second column, overwriting any existing data in the column. The two ranges do not need to start on the same row or contain the same number of rows.

LOESS Utility Button 5

The fifth button needs three range selection boxes. The first range contains the X Input and Y Input data in the first and second columns of the range. The X output data is in the second range, and the Y Output data will be placed into the third range, overwriting any existing data in the column. The three ranges do not need to start on the same row. The second and third ranges must have the same number of rows, but not necessarily the same number of rows as the first range.

LOESS Utility Button 6

The sixth button needs three range selection boxes. The first range contains the X values, the second range contains the Y Input data, the first column of the third range contains the X Output values, and the Y Output data will be placed into the second column of the third range, overwriting any existing data in the column. The three ranges do not have to start on the same row. The first and second ranges must have the same number of rows, but not necessarily the same number of rows as the third range.

LOESS Utility Button 7

The seventh button needs all four range selection boxes. The first range contains the X Input values, the second range contains the Y Input data, the third range contains the X output values, and the Y Output data will be placed into the fourth range, overwriting any existing data in the column. None of the ranges have to start on the same row. The first and second ranges must have the same number of rows, and the third and fourth ranges must have the same number of rows, but not necessarily the same number of rows as the first and second ranges.

Smoothing Parameter and Number of Points

The user can adjust the smoothness of the calculated Y Output by changing either the smoothing parameter alpha (the fraction of points used in the moving regression) or the number of points used in the moving regression. When one of these is changed, the other is updated, based on the number of points (rows) in the X Input range.

I think that values of 0.25 to 0.50 are typical for alpha, but it seems to me that if you have some logical number of points built into the data you should use that number. For example, if you have a few years of daily data, you might choose 90 points (3 months or a calendar quarter) for your analysis.

Rerunning an Analysis

When you perform a LOESS calculation with this utility, the values in the dialog are saved, and re-entered into the dialog the next time it is called on the same worksheet. Saved settings from one worksheet do not affect settings from another worksheet. If you use the output in a monthly report, this month’s settings are saved. Next month when you run the utility on the updated worksheet, your previous settings will be used as defaults, saving you a lot of time.

If you select only the first data cell of a range, the autoselection feature will select the right number of rows this month, and again next month even if data has been added or removed.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

The problem with the code in these pages is that they only labeled the active chart. The problem with this is that I often have a dozen or more charts to label, and it’s tedious to select and run the code, select and run the code, select and run the code, etc. So I recently made a minor adjustment to the code that would apply last point labels to the active chart, or to all selected charts. (You can select multiple charts by holding Shift or Ctrl while clicking on them.)

It’s almost embarrassing how long it took me to enhance the code. The reason I didn’t is another “feature” of Excel 2007. In previous versions of Excel, when I wanted to carry out an action on the selected charts on a worksheet, I could check out the selected shapes, determine which shapes were chart objects, and act on each chart object.

      Dim myChart As ChartObject
      Dim myShape As Shape

      ''' SELECTED SHAPES ON THE SHEET
      For Each myShape In Selection.ShapeRange
        ''' IS SHAPE A CHART?
        On Error Resume Next
        Set myChart = ActiveSheet.ChartObjects(myShape.Name)
        If Not Err Then
          ' check for surface chart (disallowed)
          If myChart.Chart.ChartType < 83 Or myChart.Chart.ChartType > 86 Then
            ''''''''''
            '' do what needs to be done
            ''''''''''
          End If
        End If
        On Error GoTo 0
      Next

For some reason, Excel 2007 was unable to detect which chart objects were selected, so it would process every chart object on the sheet. Not cool if you have painstakingly added a dummy series and applied custom data labels to the chart you had not selected.

I learned that you could add a shape to the sheet, and add this shape to the selection, and Excel 2007 would recognize which chart objects were actually selected. But this is a bit more contrived than I like. Not as elegant as my usual code (ha ha).

Leave it to my friend and colleague Andy Pope to find a workaround. Andy is great at looking at things a bit sideways and seeing what the rest of us have overlooked. Visit Andy’s site for a bunch of imaginative charting examples.

Anyway, Andy realized that the selection would consist of a set of objects, and you can test whether each object in the selection is a chart object. This approach works just fine in 2007 (and in 2003!).

      Dim obj As Object

      '' check for error (i.e., selection isn't a bunch of shapes)
      On Error Resume Next
      For Each obj In Selection
        If TypeName(obj) = "ChartObject" Then
          ' check for surface chart (disallowed)
          If obj.Chart.ChartType < 83 Or obj.Chart.ChartType > 86 Then
            ''''''''''
            '' do what needs to be done
            ''''''''''
          End If
        End If
      Next
      On Error GoTo 0

So finally I expanded my routine. I’ve packed it into an add-in, which works just fine in Excel 2003 and 2007. Download the zip file PTSLabelLastPoint.zip and unpack the add-in (PTSLabelLastPoint.xla). Install it using the applicable protocol in Installing an Excel Add-In in Excel 2003 or in Installing an Add-In in Excel 2007.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

Usually the data is sorted in decreasing order of the vertical value. The chart can be filled in (above) or shown in outline only (below).

Multiple series can be stacked with unique fill colors…

… or stacked unfilled with unique line colors.

The data can even include positive and negative values.

The utility was delayed several weeks because of an unexpected incompatibility in Excel 2007. But the new workaround has been tested, and it’s ready to go.

For information, visit the PTS Cascade Chart Utility page. Details about installation and use of the utility can be found at the Cascade Chart documentation page.

The utility is priced at $29 US until Thanksgiving (Thursday, November 26, 2009). After that it will be priced at $39 US.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

What makes this utility so great, you ask? The calculations were already perfectly adequate, and I didn’t change them at all. But I’ll show the new dialog, so you can see what has changed.

First, the previous interface for selecting input and output ranges was frustratingly restrictive. So I made the range selection function much more flexible. The colorful buttons on the left indicate the built-in options. In the most elementary case, all four entries (X input, Y input, X output, and Y output) are separate ranges, which can even be located on separate worksheets.

The options make range selection easier if some columns happen to be adjacent to each other, or if the same X values are to be used for both input and output. The range selection (Ref Edit) boxes and related labels update according to which option has been selected.

When the X input range has been selected, the program determines Npts, the number of points that should be used for the selected value of alpha. When the user changes alpha or Npts, the other parameter updates.

In the following case, one column serves as X input and X output (A7:A135), the adjacent column holds the Y input data (B7:B135), and the program will dump the Y output into a separate column (D7:D135).

Even this wasn’t smooth enough for me, because I got tired of scrolling up and down to select long ranges. So I made another improvement. I made the program smart enough to know that if only one row had been selected, it should use the range of data below the selected row, stopping at the first empty cell.

Couldn’t be easier.

The last change I made was to have the utility store the last LOESS parameters in each worksheet. This way, if I run a particular analysis on each sheet in a workbook, I only have to activate that sheet, run the program, and the dialog is pre-populated with the settings I need. What a time-saver!

PTS LOESS Utility Demo

Here is a demo of the new utility. This analysis only took a few minutes. I started with some Global Temperature Anomaly data from NASA.

I ran the utility to generate a smoothed temperature anomaly curve.

Then ran the utility a few more times to see the effect of alpha (number of points in the moving linear regression) on the shape of the smoothed curve. The values of 42, 25, and 12 points correspond to alpha values of 0.33, 0.2, and 0.1.

The fewer points (i.e., smaller alpha) in an analysis, the more that the smoothed curve follows local variations in the data.

Download and Install the Utility

Click this PTS LOESS Smoothing Utility link to download the utility. The download is a simple Excel add-in. Save it to any convenient directory, then install it following the instructions in Installing an Excel Add-In or Installing an Add-In in Excel 2007.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

Excel includes linear regression among its built-in functions, but there is no built-in Deming Regression capability. Users who wanted this feature had to purchase third party packages, or perform their calculations in specialized statistics programs outside of Excel.

Deming Regression Utility

I have created a new utility to address this functionality gap. It is a simple Excel add-in, with a simple user interface. The calculations are based on algorithms found in the references at the end of this article.

When installed, the utility has a simple menu item on the PTS Charts menu

or button on the Add-Ins tab

The PTS Deming Regression Utility provides two methods for calculating Deming Regression parameters. You can use custom worksheet formulas, or you can use a dialog-driven interface.

Worksheet Formulas for Deming Regression

This option does not require use of the menu or ribbon buttons. The user calculates Deming Regression parameters using simple worksheet formulas.

Referring to the regression results in the previous post

The slope, intercept, and correlation calculations are each the result of a single worksheet formula:

The Deming Regression results are returned in a three-element array formula with this syntax:

=DEMING(Y-values, X-values, Horizontal)

Y-values and X-values are required arguments which reference ranges. Each range must be one row or column only, with an even number of cells, and the two ranges must be the same size. The Horizontal argument is an optional True or False indicating the orientation of the output. The default is TRUE, and the results will be output in a row.

Don’t forget, the entire range containing the array formula is selected, the formula is typed, and it is entered by holding down CTRL+SHIFT and pressing ENTER.

Here is the row output form of the analysis:

Here is the column output form of the analysis; note the FALSE argument in the third position:

The worksheet formulas are easy to use, but if you send the workbook to a colleague, they also need the utility installed to see the results. Without the utility, all calculations are replaced by #NAME? errors.

Dialog-Driven Deming Regression

The utility features a simple dialog that helps to calculate the Deming Regression results. To use the dialog, click on the Deming Regression item in the menu or ribbon tab, shown above. A simple dialog appears.

Select the appropriate ranges for the inputs and outputs, press OK, and the program fills in the results.

Calculations made using the dialog are not lost when viewed on a machine that does not have the utility installed.

Download and Install the Utility

Click this PTS Deming Regression Utility link to download the utility. The download is a simple Excel add-in. Save it to any convenient directory, then install it following the instructions in Installing an Excel Add-In or Installing an Add-In in Excel 2007.

References

Chapter 17:  Creating  Custom  Functions, Excel for Chemists: A Comprehensive Guide, 2nd Edition. by E. Joseph Billo, Copyright 2001 by John Wiley & Sons, Inc.

Incorrect Least-Squares Regression Coefficients in Method-Comparison Analysis by P. Joanne Cornbleet and Nathan Gochman, Clin. Chem. 25/3, 432-438 (1979).

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

The Dot Plot Utility makes quick work of Dot Plots of one or more series, such as this population pyramid replacement showing US Male and Female population distribution by age group.

Like all PTS Chart Utilities, the Dot Plotter makes regular Excel charts, so you can format them to suit your needs.

Also like all PTS Chart Utilities, the Dot Plotter works in all Windows versions of Excel between 2000 and 2007. In “Classic” Excel, a Dot Plot menu item is added to the PTS Charts menu, and this menu is added if it is not already present. In Excel 2007, this Dot Plot item is added as a button to the PTS Charts ribbon tab, and this tab is added if it does not exist. A simple dialog allows the user to select some formatting options.

The PTS Dot Plot Utility is priced at $39.00 US, but for the next four weeks it is available at a discounted $29.00. If you use this chart type frequently, you owe it to yourself to check out this timesaver.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

The LOESS utility for Excel has been updated, and the interface made more flexible. The new version is described in LOESS Utility – Awesome Update, where there is a link to download the new utility.

I’ve used this utility in-house for a while, adding little enhancements here and there. I’ve come up with three main ways to use it, illustrated in the dialog screen shots below. Based on the option selected in the top of the dialog, the mode of operation is changed.

Here the data is arranged simply, with the input X and Y in two adjacent columns, and the output Y, calculated using the input X values, placed into the third adjacent column.

Here the input X and Y are in two columns, and the output Y is calculated using the input X values, but is located in another column. This is handy if you are calculating smoothed values for different values of alpha or N and placing the calculations in different columns.

Finally, the input X and Y values are in two adjacent columns, and the output X and Y are in two other adjacent columns, not adjacent to the input columns. Here the output X values need not be the same as the input X values.

When installed, the utility places a control on the PTS Charts menu. If you haven’t installed other PTS Chart Utilities, this menu will be created first.

Compare my weight over the past three years, smoothed using a seven-day moving average…

… and using the LOESS utility. The main trends are plainly visible, while the short term fluctuations have been removed.

The utility is a regular old Excel add-in, which can be downloaded in the zip file LOESS.zip (see the update below for a new version of the utility). Install this add-in using the protocol in Installing an Excel Add-In or Installing an Add-In in Excel 2007.

Try it out, and tell me what you hate about it.

Update 8 October 2009

The LOESS utility for Excel has been updated, and the interface made more flexible. It is described in LOESS Utility – Awesome Update, where there is a link to download the new utility.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
 

Box Plot with Median Indicated by Gap

The problem with the gap is that it’s hard to control its thickness closely. There is some variation from one category to the next, due I expect to rounding errors in pixel counting. If the interquartile range is small, i.e., less than twice the gap thickness, the boxes may not appear at all. Also in an earlier beta version, if the median was near zero, the boxes may appear incorrectly above or below the horizontal axis. But the decision to choose this technique was not as silly as this makes it sound.

The first box plot program I came up with, about three or four years ago, used boxes that had borders. This provides a somewhat conventional appearance, and the median is obvious.

Box Plot with Borders on Quartile Boxes – Excel View

I didn’t like this approach, however, because when Excel stacks column series, the border between stacked columns is twice as thick as the border around a single column. When the charts were copied and pasted as pictures, or exported as image files, this double border reverted to a single border (see below), but it made me crazy in the actual charts.

Box Plot with Borders on Quartile Boxes – Export View

An intermediate version of the utility removed the borders, and used different colors for the second and third quartile boxes. The problem with this approach was deciding on two colors which do not clash (e.g., not red and green) and have approximately the same visual effect (i.e., not light gray and black). And oh yeah, the colors have to be included in the user’s color palette.

Box Plot with Different Colored Quartile Boxes

So I scrapped the quartile boxes with borders and the different colored quartiles in favor of the median gaps. The gaps addressed the problems of the double thickness borders and of the different colored boxes, and if the user changed the background color of the chart, the gap was filled with the background color. Of course, everyone should want a white background.

I could have lived with the issues mentioned above (irregular gap thickness, obscuring of thin boxes), until a customer pointed out another issue with the gaps. If you convert to a logarithmic Y axis scale, the default gap is narrow at the top of the chart and wide at the bottom. The following chart exaggerates the effect.

Logarithmically Scaled Box Plot with Median Indicated by Gap

Since I now can’t live with the median gap approach, I need to select another way to display the median. Another way to show the median is with a horizontal line, which I thought I had tried, but I can find no residue of such trials. You can use a dark line or a light line.

Box Plot with Median Indicated by Dark Line

Box Plot with Median Indicated by Light Line

The light line looks like the gap, except the pixel counting for a line produces consistent line thicknesses, at least until Excel 2007, where antialiasing runs amok. But I think I prefer the dark line.

I could combine the horizontal line with a bordered box that spans both interior quartiles, giving the appearance of the bordered quartiles without a double border at the median.

To help answer this question, I’m asking my readers:

What technique should the Box and Whisker Chart Utility use to indicate the median value? Should more than one option be offered?

• Gap between Quartile Boxes
• Border on Quartile Boxes
• Differently Colored Quartile Boxes
• Dark Line at Median
• Light Line at Median
• Dark Line and Dark Interior Quartile Box
• Something Else — Please Describe

Any of these alternatives will be fairly quick to implement, and any customers will have the option to upgrade for only the price of an email.

Update 27 June 2009

Sometime late in May or early in June, I decided to switch to a discrete line to encode the median, and made the needed adjustments to my utility. This is the next-to-last option shown above. Using this approach actually simplified the utility.

Peltier Technical Services, Inc., Copyright © 2010.
 
Licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.