You can answer this question based on several sources of information.From your background in the female cycle, you know that ovulation typically occurs mid-cycle, and a typical cycle is 28 days. So, mid-cycle is day 14. You can start by looking there.However, maybe the data does not describe a typical cycle. So, using your background on the hormonal changes in the female cycle you can detect when ovulation occurs. A drop and then a rise in the BBT usually indicates the LH surge, which means that ovulation is imminent, usually within 48 hours. The day of the lowest BBT is the first day of the LH surge.From your data, you can graph it in MS Excel (or similar program) so that you visually see where the change occurs. Without that, let's look at the data.days 5 to 12, the temp drops to 36.Then on day 14, the temp rises quickly to 38.4.After that, the temp drops again.It is likely ovulation occurred on day 14.