Math and Medicine: Homework Assignment Week 9
Due on March 19
1. Get all of the new files from the website in the liver folder and read the README file.
a. Start with the program “showpat.R”. It prints out the data for that patient upon
admission, in addition to making the graphs. Find an interesting dose and time.
b. Substitute those values of L, S, and I into the program “maldplot.R” (you just edit
them in the program itself) and see if gets the right answer.
c. Add experimental error to the values of L, S, and I. What is the program most sensitive
to? When does it get mad at you (say that one of the numbers was recorded completely
wrong)?
2. Each of the blocks of code in “ROC.R” takes a value from notx to generate the receiveroperator curve. Your goal is to find a measurement that does even better than INR or
creatinine.
a. I’ve created a program “myvar.R” that shows how to do this with the sum of AST and
ALT. Run it.
b. Now change the definition of myvar. Can you get the ROC curve get really close to the
top left corner?