# FAQ: Variance in R - Review

This community-built FAQ covers the “Review” exercise from the lesson “Variance in R”.

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I tried recreating the histogram in the explanation paragraph with basic R.
I thought I’d share the code here since it includes a few styling declarations you might find useful (although ggplot seems like such a simpler choice):

``````hist(teacher_one_grades,
col=rgb(70, 130, 180, max = 255, alpha = 215),
border="white",
xlim=c(65,105),
ylim=c(0,7),
main="Student test grades in two different classes",
ylab=NA,
breaks=10)
col=rgb(255, 140, 0, max = 255, alpha = 150),
border="white",
breaks=50)
legend("topright",
c("Teacher 1 Scores", "Teacher 2 Scores"),
col=c(rgb(70, 130, 180, max = 255, alpha = 215),
rgb(255, 140, 0, max = 255, alpha = 150)),
lwd=5,
cex=0.75)
box()
``````

The only thing I could not find is how to make the borders of the bars thinner.
Let me know if any of you know how to do that.

Run the code to see two datasets that have a similar mean, but look very different.

I’m only seeing one dataset of the same authors example used throughout the lesson, and no variance value, am I missing something?

4 Likes

Came here to say this, that page is incomplete

1 Like

Yea this page is using the “Mode in R” notebook, instead of an actual review page for “Variance in R”. Would be great to see the two datasets that they talk about in the description but the code seems to not have been carried over with the review text.

This remains incomplete months later. Quite a bit of this course feels incomplete, which is a touch unacceptable.

1 Like

Years later, and this seems to haven’t been fixed yet…

Looks like well over a year later this is still an issue. I submitted a bug report…