By | 05.03.2017

# Write a C Program for Mean,Variance & Standard deviation of n numbers

Here in this c program,  we need to find out mean variance and standard deviation of n numbers, for that we need to know what is meant by mean, standard deviation and variance.

Mean : it is the average of a number of elements in a set of values. which means just add the values in a set and divide the sum with the number of elements in the set.

Variance : It is the average of squared difference of mean and the values of the data set it is  called the spread of data within a sample of data.

Standard deviation : after we got the variance we get the standard deviation by taking square root of the variance

In this c program we are taking the values for a set from the users, the mean is calculated by taking average of the sum by using a for loop . after that we need to calculate variance using the formula “value=a[i]-mean; sumsqr=sumsqr + value*value;” and var = sumsqr/ n; then now we need to calculate the standard deviation of the set, we use SD = sqrt(var) formula in this c program.

Here is source code of the C program to calculate the mean, variance & standard deviation. The C program is successfully compiled and run(on Codeblocks) on a Windows system. The program output is also shown in below.

## SOURCE CODE : :

```#include<stdio.h>
#include<math.h>
int main()
{
int i,n;
float std_dev,sum=0,sumsqr=0,mean,value,variance=0.0,a[100];
printf("Enter value of n : ");
scanf("%d",&n);
printf("\nEnter numbers : ");
for(i=0;i<n;i++)
{
printf("\nNumber %d : ",i+1);
scanf("%f",&a[i]);
sum=sum+a[i];
}
mean=sum/n;
sumsqr=0;
for(i=0;i<n;i++)
{
value=a[i]-mean;
sumsqr=sumsqr+value*value;
}
variance=sumsqr/n;
std_dev=sqrt(variance);
printf("\nMean of %d numbers = %f\n",n,mean);
printf("\nVariance of %d numbers = %f\n",n,variance);
printf("\nStandard deviation of %d numbers = %f\n",n,std_dev);
return 0;
}```

## OUTPUT : :

```Enter value of n : 7

Enter numbers :
Number 1 : 23

Number 2 : 45

Number 3 : 12

Number 4 : 66

Number 5 : 58

Number 6 : 31

Number 7 : 67

Mean of 7 numbers = 43.142857

Variance of 7 numbers = 405.551025

Standard deviation of 7 numbers = 20.138298```
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Category: Arrays Programs C Programming Tags:

My name is Tunde Ajetomobi, a Tech Enthusiast and Growth Hacker. I enjoy creating helpful content that solves problem across different topics. Codezclub is my way of helping young aspiring programmers and students to hone their skills and find solutions on fundamental programming languages.

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