The amount of Jen's monthly phone bill is normally distributed with a mean of $55 and a standard deviation of $12. A) using the Empirical Rule, what percentage of her phone bills are between $19 and $79? B) what z-score corresponds to a $75 phone bill? Round answer to 2 decimal points and show calculations you used to arrive at an answer. C) would it be considered unusual for Jen to get a $30 monthly phone bill? Explain