Should I worry that ....

1) less than 10% of my students have even picked up the practice exam questions less than 48 hours before the first exam

2) only about 55 % have turned in all 4 of the homework assignments due before this point in the semester

3) according to the few questions I have gotten---they are not seeing the difference between memorizing a definition and being able to apply the material to a situation. [Even though I told them knowing a defnition would be of little help unless they then knew what to do with the concept and all of the in-class work and homework assignment have focused on application.]

4) I worry too much about my students? Sometimes it seems like the more 'safeguard' things I put in place, the more they blame me when they do not learn the course material. Maybe I should try to transform into one of those 'hard ass profs' that just gives a midterm and a final -average the 2 scores --> voila final grade.