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  1. ondansetron

    Rep and Seq

    Was tinkering with rep and seq today and wondering about the following: > rep(c(5,12,13), each=2) [1] 5 5 12 12 13 13 I wondered what would happen if I specified seq(1:3) for each=... I assumed this would happen: 5, 12, 12, 13, 13, 13 but instead got: > rep(c(5,12,13), each=c(seq(1:3...
  2. ondansetron

    Rolling 4 dice, probability of a sum=S

    Working on a problem (not homework for me) regarding the probability of a particular sum achieved by rolling n fair 6-sided dice. The specific problem required me to find the probability that four dice are rolled and the sum is 21. I said 6^4 possibilities = denominator. The only possible...
  3. ondansetron

    R programming

    This is a module in the Swirl package that I've had some trouble understanding their explanation, although I'm able to successfully complete the assigned task. I was hoping someone would provide a better explanation of what's going on in the following: # Let's explore how to "unpack" arguments...
  4. ondansetron

    R [ugly] and R [studio]

    Not sure the official name of the ugly bare-bones syntax interface for R, sorry. If I install/update a package in the R[ugly] is it automatically installed/carried into R studio? If not, is there an easy way to make this happen?
  5. ondansetron

    Kappa for nonsquare tables

    I have two raters who could have assigned any of 16 ratings to a subject. There are some categories that were not used, so the resulting table is not square and SAS will not give me the Kappa (Cohen's) for it. I'm having trouble figuring out how to do this quickly and efficiently to get the...
  6. ondansetron

    ERROR: Row or column names must be character

  7. ondansetron

    In search of differences of non-mutually exclusive k categories over g groups

    I conceptualize this problem to be similar to a 2x4 test of independence with a chi squared test statistic, but I recognize the problem is different. Suppose we have 2 groups with 20 participants in each group. The groups are mutually exclusive. For any given participant they have some...
  8. ondansetron

    Two for one: Unique variable values

    I used the search and did not find the answer, and I've been poking in SAS documentation without much luck. problem 1) I would like to tell SAS to randomly select x% of my spreadsheet subject to the constraint that all values for a particular variable are unique. For example, if I have a sheet...
  9. ondansetron

    Summing number of "successes" over multiple related binary variables for a patient

    Hey everyone, I'm trying to find a more efficient way to tell SAS to look at an observation and count the number of "successes" when looking at specific variables and then to create a new variable that is the count of "successes" for this observation. OBS X1 X2 X3 1 1 0 0 2...
  10. ondansetron

    read.csv adds weird character to my first column header

    New one-off question: I am trying to learn importing data with R. I am following Mike Marin's Youtube lectures. I saved his excel sheet as .csv and tried the read.csv command, and everything seems to go well. I am totally new to R, essentially. When I try to view the data, the console shows a...