1. The problem statement, all variables and given/known data The door frames used by a builder are of one standard height, 1.83m. The heights of men are normally distributed with mean 1.73m and standard deviation 0.064m. The door frames are to be used in a department store. It is known that women outnumber men in the ratio 19:1 in the store and the proportion of women taller than the door frame is 0.00069. Find the proportion of people for whom a frame height of 1.83m would be too low. 2. Relevant equations 3. The attempt at a solution I thought it should be 19/20*(0.99931)+1/20*(0.9409) But the answer is 19/20(0.00069)+1/20(0.0591) But 0.00069 and 0.0591 are the probabilities for men and women taller than the door frames. So i don't understand.