# Programming Fundamentals/Math Statistics with Arrays

## Overview

Statistics is a branch of mathematics dealing with the collection, organization, analysis, interpretation, and presentation of data. Common statistical methods include mean (or average) and standard deviation.

## Discussion

Arrays can store words, letters/characters (strings) and numbers (integers/floats). Any type of array containing words, numbers or a combination can use a built-in function like `len`(Python exclusive) to find the number of elements in an array to help display output and parse lines. All arrays can also handle functions that allow the user to sort array values from highest to lowest (or vice versa). Other functions are only intended to handle arrays with numbers. For example, When arrays contain numbers, the elements of the array can be added together using the `sum` function. Since the built-in `sum` function cannot handle strings without producing an unsupported operand type error, we use this function only to add numbers, rather than join strings together.

We will continue learning about the `sum` function (also known as totaling) in this module. In the example below, the `sum` function totals the array passed to it. Other mathematical functions often associated with statistics such as: average, count, minimum, maximum, standard deviation, etc. are often developed for processing arrays.

### Pseudocode

```Function Main
Declare Integer Array ages
Declare Integer total

Assign ages = [49, 48, 26, 19, 16]

Assign total = sum(ages)

Output "Total age is: " & total
End

Function sum (Integer Array array)
Declare Integer total
Declare Integer index

Assign total = 0
For index = 0 to Size(array) - 1
Assign total = total + array[index]
End
Return Integer total
```

### Output

```Total age is: 158
```

## Key Terms

sum
is a built-in function, which adds the elements of an array together.
len
is a built-in function and it returns the number of items in an object.