Final answer:
The MATLAB function designed to calculate the average is the 'mean function'. It adds all array elements and divides the sum by the number of elements to return the average.
Step-by-step explanation:
The MATLAB function that returns the average by adding all the values in an array and dividing by the number of elements is the mean function.
If you have an array of numbers, let's say A = [1, 2, 3, 4, 5], and you want to calculate the average of these numbers, you would use the mean function in MATLAB like this: avg = mean(A). This function will sum all the values within the array (which is what the sum function does), and then divide that sum by the number of elements in the array to find the average value.
The correct answer from your options is A) mean function.