A woman recorded the length of her menstrual cycle for six cycles.
The Table shows her results.
Table
| Cycle | Length of cycle in days |
|---|---|
| 1 | 26 |
| 2 | 30 |
| 3 | 28 |
| 4 | 33 |
| 5 | 27 |
| 6 | 30 |
Ovulation usually takes place about 14 days before the start of the next menstruation.
Calculate the mean length of her menstrual cycle.
Use your answer to (a) to calculate the day of the cycle on which ovulation is most likely to take place.
The woman is trying to become pregnant.
Explain why it is difficult for her to predict when she is most likely to become pregnant.
48 exam-style questions on Edexcel GCSE Biology 7.2 Reproductive hormones, covering 7.2.1 Stages of the menstrual cycle, 7.2.2 Hormonal control of the menstrual cycle, 7.2.3 Hormonal contraception, 7.2.4 Evaluating contraception methods, and 7.2.5 Hormones in Assisted Reproductive Technology. Each one has a worked solution and a mark scheme showing where the marks go.