Source code for simplestatistics.statistics.root_mean_square

import math
from .sum import sum

[docs]def root_mean_square(x): """ Root mean square (RMS) is the square root of the sum of the squares of values in a list divided by the length of the list. It is a mean function that measures the magnitude of values in the list regardless of their sign. Args: x: A list or tuple of numerical objects. Returns: A float of the root mean square of the list. Examples: >>> root_mean_square([-1, 1, -1, 1]) 1.0 >>> root_mean_square((9, 4)) 6.96419413859206 >>> root_mean_square(9) Traceback (most recent call last): ... TypeError: root_mean_square() expects a list or a tuple. """ if type(x) not in [list, tuple]: raise TypeError('root_mean_square() expects a list or a tuple.') squares = [] squares = [pow(num, 2) for num in x] sum_of_squares = sum(squares) ms = sum_of_squares / len(x) rms = math.sqrt(ms) return(rms)