How many participants would be required for a complete factorial 4 5 between-subjects design with ...

How many participants would be required for a complete factorial 4  5 between-subjects design with three observations per cell?
 
  What will be an ideal response?

Question 2

Suppose you are interested in how well students perform on a standardized math-achievement test after they have completed a six-week math unit in either a computer-assisted class, a videotaped course, or a regular classroom and comparing the performance of male students against that of female students.
 
  a. What is the dependent variable?
  b. What are the independent variables?
  c. How many levels does each independent variable have?