The upper arm length of females over 20 years old in a country is approximately Normal with mean 35.6 centimeters (cm) and standard deviation 2.3 cm. Use the 68-95-99.7 rule to answer the following questions. (Enter your answers to one decimal place.)

a. What range of lengths (±0.1 cm) covers almost all (99.7%) of this distribution?
b. What percent (±0.1%) of women over 20 have upper arm lengths below 33.5 cm?