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Go back to STAT545A home

Descriptive statistics on HW and course marks

There were six homework assignments:

  • HW1 Write short R script, publish it as a Gist, compile it to an HTML notebook and publish that to RPubs
  • HW2 Basic intake and exploration of Gapminder data; package in an R Markdown document, publish it as a Gist, compile to HTML and publish that to RPubs
  • HW3 Data aggregation with plyr (plus usual publishing stuff)
  • HW4 lattice graphics (plus usual publishing stuff)
  • HW5 ggplot2 graphcs (plus usual publishing stuff)
  • HW6 Build a modest, automated data exploration and visualization pipeline and publish it to web

Assignments were marked on a coarse scale of check minus, check, check plus. Of course, we eventually needed a larger range and used check minus minus and check plus plus. HW1 - HW4 were marked by the TA and vetted by the instructor. HW5 and HW6 were marked by TA and instructor, with instructor making final decisions. Instructor ran all the pipelines submitted for HW6. Yikes.

Here are barcharts of the HW marks for STAT545A in 2013 (typically ~34 registered students or auditors submitted work):

Coarse marks were converted to numbers like so:

+--------+--------+ | coarse | number | | mark | | +========+========+ | c-- | 76 | +--------+--------+ | c- | 79 | +--------+--------+ | c | 85 | +--------+--------+ | c+g | 90 | +--------+--------+ | c+ | 93 | +--------+--------+ | c++ | 98 | +--------+--------+

The mark c+g was used only on HW6. It was "check plus, Gapminder division". This was needed to reward very strong work, while being fair to those who reached a similar level of accomplishment with a novel dataset.

Overall course marks were computed as a weighted average of the 6 homework assignments. Weights for HW1 and HW2 were 1. Weights for HW3, HW4, HW5, and HW6 were 3. In case you're worried, the weighted.mean() function scales the weights to sum to 1!

Here are the course marks plotted against rank. There were lots of ties. Only 33 participants completed all 6 HWs, since some auditors skipped assignments and for them no course mark was computed:

Here is a densityplot of the course marks, with actual marks depicted as dots, jittered in the y-direction:

Here are summary statistics of course marks in STAT545A in 2011, 2012, and 2013:

## 2013
## Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
## 79.00   84.00   86.00   86.27   88.00   94.00 

## 2012
##  Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
## 81.68   83.68   89.68   83.51   91.42   92.80

## 2011
##   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
##  77.98   81.41   82.83   83.81   84.26   94.46