Displaying the number of elements larger than the average of an array
A few extra comments:


define main at the bottom so that prototypes are unnecessary
define local functions 'static'
if you are going to use EXIT_SUCCESS then also use EXIT_FAILURE
your comments are just noise (no useful information) and should be deleted
add a \n at the end of the final printf  (which is missing count)
you don't check for n being greater than SIZE, only for zero (although
the error printf says n is too big)
define loop variables in the loop and always use braces, even when not necessary:

for (int i=0; i&lt;n; ++i) {
    // do something
}

findAverage and countAboveAverage should declare arr as const

static double findAverage(const int arr[], int n);

personally I'd avoid using unsigned types (suggested by @Sulthan) as it often
leads to unexpected arithmetic results.  If you do use it, make sure you
enable the necessary compiler warnings.