[Data Analysis, Module 2] Requiring exact order & separation of answers is bad

[nathantypanski]

I struggled for quite a bit attempting to solve the following problem:

PROGRESS: << (X) (X) (X) (X) (X) (X) (X) (X) (X) ( ) >> (85% Complete)

An OUTLIER is an observation that is unusual or extreme relative to the other values in 
the data set. Outliers are useful in identifying a heavy skew in a distribution, 
and may signify a data collection or data entry error to a scientist. 
There are many different conventions for identifying outliers within a data set.

...

PROGRESS: << (X) (X) (X) (X) (X) (X) (X) (X) (X) (X) >> (88% Complete)

When looking at the box plot, which car types appear to have outliers?
Separate your answers with a comma.

The following are the answers I tried first:

midsize, small

Thinking perhaps it does not accept answers with spaces in between (it does say to separate with commas), I tried:

midsize,small

Ok, maybe it wants 'small' to come first:

small,midsize

Still nothing. Quotes?

'midsize','small'

After much rage, I finally came to:

ANSWER: small, midsize

You got it!

It doesn't really make sense for small to have to come before midsize, with a comma and space separating the two when separate your answers with a comma is all that is requested.

Perhaps a means should be provided for accepting a list of answers as a solution to a problem, as opposed to just one particular string? Then some parsing could be done to verify that the user's input matches the list, and everybody would be happy.

[WilCrofter]

I went through the same thing. The Instructor's Manual (PDF) provides a prototype mechanism for alternative right answers (alternatives on different lines of the same spreadsheet cell. No alternatives were given in this particular case.) Improvement is obviously needed. A couple of fixes have been considered so far, but all create other problems. Head scratching is in progress, but we're not there yet.

[robertpenner]

I was banging my head against the wall trying to pass the same question. I tried every combination as you, except for small, midsize. At least now I can move on.

[ncarchedi]

This problem appears to be platform specific, as I'm not able to replicate it on my machine (Windows 7, R version 3.0.2). We are in the process of coming up with a more robust way of checking for the correct response. If you are having this problem, please let us know your operating system and R version.

Thanks, Nick

[nathantypanski]

Arch Linux
3.10.17 LTS kernel
R version 3.0.2 (2013-09-25) -- "Frisbee Sailing"

Can confirm the problem still occurs with these (perhaps updated) version numbers. I was able to replicate the results of my original post exactly.

[ncarchedi]

We have not solved this problem yet. Apologies for the delay, but please be patient with us. We are just a small group of busy people working on swirl in our spare time. Hope to have a fix soon.

Nick

On Sat, Nov 2, 2013 at 8:14 PM, Nathan Typanski notifications@github.comwrote:

Arch Linux 3.10.17 LTS kernel R version 3.0.2 (2013-09-25) -- "Frisbee Sailing"

Can confirm the problem still occurs with these (perhaps updated) version numbers. I was able to replicate the results of my original post exactly.

— Reply to this email directly or view it on GitHubhttps://github.com/ncarchedi/swirl/issues/22#issuecomment-27635780 .

Nicholas A. Carchedi ScM Student, Biostatistics Johns Hopkins Bloomberg School of Public Health 301.802.0573 | nick.carchedi@gmail.com

[IamGianluca]

I can reproduce the issue on Linux Mint 15 (64-bit) 3.8.0-25-generic R version 3.0.2 (2013-09-25) -- "Frisbee Sailing"

[ncarchedi]

Problem solved! This is now a multiple choice question -- no longer sensitive to spaces, commas, etc. Should have gone this route from the beginning, but lesson learned.

Nick