I'm running this simulation where you roll a die in R and record the result. Part of the code I got from my professor says cumulative.sums = cumsum(roll == 1)
I'm not exactly sure what this code means. and here's the result I got. trial.num roll.result cumulative.sums proportion [1,] 1 6 0 0.0000000 [2,] 2 3 0 0.0000000 [3,] 3 1 1 0.3333333 [4,] 4 3 1 0.2500000 [5,] 5 1 2 0.4000000 [6,] 6 3 2 0.3333333
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$\begingroup$You can always google:
And this function is shown very clearly by its name - cumulative sum: It is summing all the elements in a vector, the argument of this function.
In your example the vector "roll==1" is extracting the indicator of each roll results equal to 1 as a vector, so essentially you are counting the number of 1's in the vector "roll".
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