Answer:
a) 91.4%
b) 37.6%
c) 26.8%
Step-by-step explanation:
For each of these, we'll get a z-score, then use our calculators to find the area using normalcdf (on TI-84, 2nd->VARS->2)
a) z = (9-6.4) / 1.9 = 1.368
normalcdf(-999,1.368) = .914 = 91.4%
b) z = (7-6.4) / 1.9 = .316
normalcdf(.316,999) = .376 = 37.6%
c) normalcdf(.316,1.368) = .268 = 26.8%
