So, you want to calculate the standard deviation step-by-step. So, firstly, you should calculate the sum of the differences of all data points with the mean.

Have a variable called count and set it to the value 0.

For that, you loop through the data set with a variable, say i and subtract i every time with the mean. Mean can be calculated as mean(dataset).

Add the result of every loop iteration to count, by count += (i-mean)^2

Now, divide the count variable by len(dataset) - 1

The result is the variance. So, for calculating the standard deviation, you have to square root the above value.

In R, you do this as: sqrt(variance)

Finally, the result you get after applying the square root is the Standard Deviation.

So, you want to calculate the standard deviation step-by-step. So, firstly, you should calculate the sum of the differences of all data points with the mean.

Have a variable called count and set it to the value 0.

For that, you loop through the data set with a variable, say i and subtract i every time with the mean. Mean can be calculated as mean(dataset).

Add the result of every loop iteration to count, by count = count + (i-mean)^2

Now, divide the count variable by len(dataset) - 1

The result is the variance. So, for calculating the standard deviation, you have to square root the above value.

In R, you do this as: sqrt(variance)

Finally, the result you get after applying the square root is the Standard Deviation.