How do i compute frequency of the numbers in the range,let's say 10-19,using rand number generator array with 50 int?

I have this code so far:

```
$arr = array_fill(0, 50, NULL);
for ($i = 0; $i < 50; $i ++) {
$arr[$i] = rand(10, 19);
}
```

but not sure if rand() assigned correctly .Thanks for any solution.