function ghostCount(index) {
  if (document.easyform.ghost[index].checked) {
    return 1;
  } else {
    return 0;
  }
}

function validGhost() {
  if ( (ghostCount(1) + ghostCount(2)+ ghostCount(3)) <= 2 ) {
    return true;
  } else {
    alert("Please answer the ghost question."); 
    return false;
  }
}