How can I show how many questions?
You can use this function for getting total published questions:
ap_total_published_questions()
For counting users, you can try this:
$result = count_users();
foreach($result['avail_roles'] as $role => $count){
    if( 'ap_participant' == $role ) echo $count;
}
  dce  commented   
None of the above…
 Probably I’m missing some code before (I’m not a coder)
 Thank you anyway

  dce  commented   
I did it work!
 Count users works perfect but
 Count Total questions shows a WRONG number (they are 11 and it shows 1 (1 is published by a specific Role)… How to show ALL?
 Thank you again
 
 
And the number of Users with a certain Role?