You need to read more numbers. You read one value before your loop. You could do something like
int number;
while((number = input.nextInt()) != 0) {
total += number;
count++;
if(number > 0){
positive++;
} else if(number < 0) {
negative++;
}
} // <-- end loop body.
float average = total / (float) count; // <-- not integer math.
System.out.println("The number of positives is " + positive);
System.out.println("The number of negatives is " + negative);
System.out.println("The total is " + total);
System.out.println("The average is " + average);