As the red line clearly demonstrates, ...

      I have been at lots of business meetings where the speaker would say something like, "As the red line clearly demonstrates, ..."

      I would quickly look up at two particular co-workers. We all had that same rolling of the eyes look. When you have color-challenged issues, that red line does not clearly demonstrate anything to us. (And yes, the three of us knew we all had color issues.)

      I wrote the R code for this graph. But I used a random number to decide which line is red and which is green, so I don't know which line is which.

      I am not color-blind. I am color-challenged. I see some colors, but probably not as many as most people see. I don't distinguish between red and green well. I also don't distinguish between blue and purple well because of the red element of purple, and similarly for other combinations.

      In my earliest elementary school years I had a box of 8 Crayola crayons, and I did just fine. My problems began when Crayola started adding more and more colors including combinations like green yellow and yellow green. Here are the original eight colors, which I still identify just fine. (There is no meaning to the heights of the bars.)

      One source suggests approximately 1 in 12 men have color issues, but only 1 in 200 women.

      Color-challenged people often have coping strategies. I can see when the top traffic light is on, so I will stop my car. But in my heart, I don't think it is red, but more of an orange. Similarly I can see when the bottom traffic light is on, but I think it is more of an off-white than green. As long as no one flips the positions, I am fine. A single flashing light is a probllem though.

      When I see an 8-sided stop sign, that's what I consider red. And I recognize Taylor Swift wears what I consider a very red lipstick, but I assume she wears more than one shade and I cannot distinguish among them.

      The speaker with the two-line graph could have used the different shapes, or different graph line types dashes and dots, in the talk. Or the speaker could have used color-blind friendly color palettes. If you are creating visualizations for others, please think about these things.

      And ladies, that purple lipstick looks very nice on you. Oh, it's not purple ... ?

      The R code is as follows:

# Two lines with random colors
x <- seq(1:5)
y <- seq(1:5)
z <- seq(5,1, by = -1)

color_1 <- "#00B050"
color_2 <- "#FF0000" 

r <- runif(1,0,1)
r
if (r < .5){
  col_y <- color_1
  col_z <- color_2
} else{
  col_y <- color_2
  col_z <- color_1
}

plot(x,y, type="b", pch = 18, cex = 2.5, lwd = 2.5, col=col_y, ylab="", xlab="", 
     main="As the red line clearly demonstrates ...", cex.main = 1.5,
     sub="If r<.5 then (green, red), else (red, green)",
     font.sub = 2, cex.sub = 1.5)
par(new=TRUE)
plot(x,z, type="b", pch=20, cex = 2.5, lwd = 2.5, col=col_z, ylab="", xlab="")
legend("topright", legend= c("Increasing", "Decreasing"), pch = c(18, 20),
       col = c(col_y, col_z), cex=1.5, text.font=2)

# Original 8 Crayola Crayons
title <- c("Original 8 Crayola Crayons")
subtitle <- c("According to https://en.wikipedia.org/wiki/History_of_Crayola_crayons")
temp <- c(5,7,6,4,8,5,2,5)  # meaningless
colors <- c("red", "yellow", "blue", "green", "orange", "brown", "violet", "black")
hex <- c("#FF0000", "#FFFF00", "#0000FF", "#008001", "#FF6600", "#964B00", "#6A0DAD", "#000000")
barplot(temp, col=hex, main=title, sub=subtitle, names.arg=colors,
          cex.main = 1.5, font.axis = 2, font.sub = 2, cex.sub = .75 )
       

End

Taylor Swift and Data Analysis

Taylor Swift and Data Analysis. by Jerry Tuttle

Who will be the most talked-about celebrity before, during, and after the Super Bowl?

The color-challenged math student

If you are part of the 92% majority (that was not supposed to be a political comment), then you can see a number inside that circle.  But I can't.  The common description for my condition is being colorblind, although I prefer the more politically correct "color-challenged".  I am not truly colorblind.  I see some colors, just not as many as you see, and I get especially confused between red and green, shades of red and green, and colors containing either red or green (for example blue versus purple).

I will stop my car for the top (or left) traffic light, but I don't really think it is red. I would wear a red tie with a green-striped shirt if no one stops me, so I try not to own shirts with green.  Or to wear ties.  I'm never quite sure if the meat is cooked enough. You won't see me choosing colors of house paint or women's makeup shades, and I won't be disabling colored wires for the police bomb squad.  So generally I have learned to live with this minor inconvenience, and the accompanying jokes, which has not impeded my career choice.

But the world of math is not as black and white as it used to be.  A textbook author would never graph two curves in the same color.  But if y = .5e^x  is in red and y = x² is in green, I am going to be confused as to which curve is greater in 1 < x < 3.  I also get confused by multi-color pie charts where some of those colors start to blend together.  And if you really want to lose me, just show me one of those colored maps with ten or so different colors representing ten different levels of the amount of rainfall.

So if you are a teacher with control over such things, please be aware that some small percent of your students could be color-challenged and they may not even know it.  The best thing you can do is provide labels in addition to different colors.  Another possibility is to provide different kinds of patterns (see Excel's FORMAT, FILL, PATTERN STYLES).  Lastly, choose among colors we are more likely to recognize, and especially avoid red AND green together.

Have you had any difficulties in math with a color-challenged math student?