Reading Questions Answer Checker
To check your answers put them in the appropriate box and click the ‘Check’ button. Every checker box can do arithmetic and calculate standard functions (see calculator help). If you give decimal answers, give them to at least 3 decimal places.
As you work you should have pencil and paper handy for calculations and thinking!
Note: some questions ask for a formula. For the checker we ask you to plug a value into the formula. For your pset you still need to give the whole formula.
//DEBUG PARAMETERS //Because we don’t show solutions for pset checkers we use //this to give a showanswer button during the debugging phase var debugans = undefined; //release //var debugans = kDebugAnswer; //debug problemNumber = 0; wl(“Calculator”); writecalculator(“psetcheckcalcid”, “Calculate”); whr(kdivcol,kdivwid);
//Problem 1 problemNumber++; wl(problemheader(problemNumber)); wl(kp); var s; var partName, problemName, buttonLabel, answerArray, correct; s = [“Using what you’ve learned about R, simulate rolling one die 100000 times and compute the average of the 100000 rolls.", kbr, “(You should use the sample() and mean() functions.)"]; wl(s.join(’ ‘)); wl(kp); partName = problemNumber; problemName = “prob” + partName; buttonLabel = “Check problem " + partName; writeNumericBox(partName+"id”, 3.5, buttonLabel, 0.05, “3.5 (anything close)"); whr(kdivcol,kdivwid);
//Problem 2 problemNumber++; wl(problemheader(problemNumber)); wl(kp); var s; var partName, problemName, buttonLabel, answerArray, correct; s = [“In a sequence of numbers a run is a subsequence of the same number.", “For example “, kp, ksp,ksp,ksp,"(1,1,1,2,3,3,3,1,1)", kp, “has a run of 1’s of length 3, a run of 2’s of length 1, “, “a run of 3’s of length 3 and a run of 1’s of length 2.", kp, “The R function rle() helps compute the run lengths in a sequence. “, “Try running the following code”]; wl(s.join(’ ‘)); wl(kp); s = [rcmdna(“x = c(1,1,1,2,3,3,3,1,1)"), kbr, rcmdna(“y = rle(x)"), kbr, rcmdna(“y”)]; wl(s.join(’ ‘)); wl(kp); s = [“You should see the following”, kbr, rtext(“Run Length Encoding”), kbr, ksp,ksp,ksp, rtext(“lengths: int [1:4] 3 1 3 2”), kbr, ksp,ksp,ksp, rtext(“values : num [1:4] 1 2 3 1”)]; wl(s.join(’ ‘)); wl(kp) s = [“The lengths vector shows the runs in " + rtext(“x”), " and the values vector shows the number used for each run. “, “To pick out just the lengths vector you use the command:", ksp, rtext(“y$lengths”), kp, “You should see: " + ksp + rtext("[1] 3 1 3 2”)]; wl(s.join(’ ‘)); wl(kp) s = [“Run the code”, kbr, rtext(“set.seed(10)"), kbr, rtext(“y = rbinom(20,1,.5)")]; wl(s.join(’ ‘)); wl(kp) s = [rtext(“y”), " is a vector of 0’s and 1’s of length 20. Use “, rtext(“rle(y) “), " to find the length of the longest run in “, rtext(“y.")]; wl(s.join(’ ‘)); wl(kp) partName = problemNumber; problemName = “prob” + partName; buttonLabel = “Check problem " + partName; writeNumericBox(partName+"id”, 5, buttonLabel, 0.001, kuseCorrectVal); whr(kdivcol,kdivwid);