Answer:
The formula to calculate APY is (1 + (i/n))^n - 1
where i is the interest rate and n is the number of compounding periods.
Monthly APY = (1 +(0.055/12)^12 -1
APY = 0.0564 = 5.64%
Quarterly APY = (1 +(0.055/4)^4 -1
APY = 0.0561 = 5.61%
Difference = 5.64 - 5.61 = 0.03% more when compounded monthly.
The APY is more when compounded monthly, because there are more compound periods.
