null hypothesis?

If fertilizer is added to the soil rosebushes are growing in, then the rosebushes will grow larger than rosebushes grown without fertilizer.
If professional athletes sleep 12 hours a night, then their performance will be the same as other professional athletes who only sleep 8 hours a night.
If I read the chapter before attempting my daily work, I will earn better grades than another student who does not read the chapter before attempting his daily work.
If plants are exposed to 12 hours of light per day, then the plants will grow faster

Question

null hypothesis? 
  
 If fertilizer is added to the soil rosebushes are growing in, then the rosebushes will grow larger than rosebushes grown without fertilizer. 
 If professional athletes sleep 12 hours a night, then their performance will be the same as other professional athletes who only sleep 8 hours a night. 
 If I read the chapter before attempting my daily work, I will earn better grades than another student who does not read the chapter before attempting his daily work. 
 If plants are exposed to 12 hours of light per day, then the plants will grow faster

anonymous · Answer

to many questions in one post