Pure-Bred Dogs Competing in Shows Must Often Meet Specific Height

Short Answer

Pure-bred dogs competing in shows must often meet specific height criteria to be considered to be within the breed standard. A new breed of dog, the pug-cock-a-poo, has been approved by a kennel club. The variance of pug-cock-a-poo height is known to be 2.25 inches squared. You would like to estimate the mean height of all pug-cock-a-poo breeds of dogs.
A) Find the appropriate sample size to achieve a margin of error of 0.3 when maintaining a 90% level of confidence.
B) Find the appropriate sample size to achieve a margin of error of 0.3 when maintaining a 95% level of confidence.