statistics

How to Calculate the sample mean, standard deviation, and variance in C++ from random distributed data and compare with original mean and sigma

There is no standard deviation function C++, so you’d need to do write all the necessary functions yourself — Generate random numbers and calculate the standard deviation. double stDev(const vector<double>& data) { double mean = std::accumulate(data.begin(), data.end(), 0.0) / data.size(); double sqSum = std::inner_product(data.begin(), data.end(), data.begin(), 0.0); return std::sqrt(sqSum / data.size() – mean * mean); … Read more

In R, how to turn characters (grades) into a number and put in a separate column

Often you can use a named vector to do these sorts of mapping operations simply: students <- data.frame(name=c(“J. Holly”,”H. Kally”, “P. Spertson”, “A. Hikh”, “R. Wizht”), CRSE_GRADE_OFF=c(“A”,”D”,”E”,”A”,”A”)) scores = c(A=1, B=2, C=3, D=4, E=5, F=6) students$grade <- scores[as.character(students$CRSE_GRADE_OFF)] students # name CRSE_GRADE_OFF grade # 1 J. Holly A 1 # 2 H. Kally D 4 … Read more