ok there's this TBR CBT question that discusses how variable the 28-day menstrual cycle is. one question says if a woman's cycle is 20-24 days, her expected period of ovulation is expected to be _____ days. well, normally it's on day 14. SO, with a 28-day normal cycle, you would assume it occurs half way through the cycle (14/28). So, I chose 10-12 days because that would be the midpoint range for a 20-24 cycle. It said I was wrong and that the answer is 7-9. the answer explanation says assuming the luteal phase is fairly constant in all individuals, you subtract 14 from the 22 day average of 20-24 giving you 7-9. HOWEVER, no where in the passage does it say the luteal phase is consistently 14-days across all women. ONLY in the answer does it make that assumption, an unfounded assumption. how would the test taker know to make that assumption? they wouldn't. they would do what i did and get it wrong. is this simply a poorly written question since it is from a practice test company?