Python Math: Calculate the standard deviation

Last update on April 24 2025 12:44:20 (UTC/GMT +8 hours)

57. Standard Deviation Calculator

Write a Python program to calculate the standard deviation of the following data.

Sample Solution:

Python Code:

import math
import sys

def sd_calc(data):
    n = len(data)

    if n <= 1:
        return 0.0

    mean, sd = avg_calc(data), 0.0

    # calculate stan. dev.
    for el in data:
        sd += (float(el) - mean)**2
    sd = math.sqrt(sd / float(n-1))

    return sd

def avg_calc(ls):
    n, mean = len(ls), 0.0

    if n <= 1:
        return ls[0]

    # calculate average
    for el in ls:
        mean = mean + float(el)
    mean = mean / float(n)

    return mean

data = [4, 2, 5, 8, 6]
print("Sample Data: ",data)
print("Standard Deviation : ",sd_calc(data))

Sample Output:

Sample Data:  [4, 2, 5, 8, 6]                                                                                 
Standard Deviation :  2.23606797749979

Pictorial Presentation:

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to compute the standard deviation of a list of numbers using the statistics.stdev() function.
• Write a Python function to calculate the standard deviation manually from a list of numbers and compare the result with statistics.stdev().
• Write a Python script to accept a sequence of numbers from the user, compute the standard deviation, and print the result.
• Write a Python program to generate a random dataset, compute its standard deviation, and display the result with 5 decimal places.

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