 # C Program to Calculate Standard Deviation

In this example, you will learn to calculate the standard deviation of 10 numbers stored in an array.

To understand this example, you should have the knowledge of the following C programming topics:

This program calculates the standard deviation of an individual series using arrays. Visit this page to learn about Standard Deviation.

To calculate the standard deviation, we have created a function named `calculateSD()`.

## Example: Population Standard Deviation

``````// SD of a population
#include <math.h>
#include <stdio.h>
float calculateSD(float data[]);
int main() {
int i;
float data;
printf("Enter 10 elements: ");
for (i = 0; i < 10; ++i)
scanf("%f", &data[i]);
printf("\nStandard Deviation = %.6f", calculateSD(data));
return 0;
}

float calculateSD(float data[]) {
float sum = 0.0, mean, SD = 0.0;
int i;
for (i = 0; i < 10; ++i) {
sum += data[i];
}
mean = sum / 10;
for (i = 0; i < 10; ++i) {
SD += pow(data[i] - mean, 2);
}
return sqrt(SD / 10);
}
``````

Output

```Enter 10 elements: 1
2
3
4
5
6
7
8
9
10

Standard Deviation = 2.872281
```

Here, the array containing 10 elements is passed to the `calculateSD()` function. The function calculates the standard deviation using mean and returns it.

Note: The program calculates the standard deviation of a population. If you need to find the standard deviation of a sample, the formula is slightly different.