You wish to estimate, with 95% confidence, the proportion of camcorders that need repairs or have problems by the time the product is 5 years old.  Your estimate must be accurate within 5% of the true proportion.

   
a.  Find the minimum sample size needed, using a prior study that found that 25% of the      camcorders needed repairs or had problems by the time the product was five years old.


b.  If no preliminary estimate is available, find the minimum sample size needed.

c.  Compare the results from a & b.