Hi Normal Distribution: µ = 69.5 and σ = 2.3 Using TI or similarly an inexpensive calculator like a Casio fx-115 ES plus Continuous curve Pick 'one' P(64.7 > x > 73.4) = normalcdf(64.7,73.4, 69.5, 2.3) = .9366 Important You feel comfortable using Your calculator. Wish You the Best in your Studies.