Pretesting is a broad term that incorporates many different methods or combinations of methods. This pamphlet briefly describes eight suggested techniques that can be used to pretest questionnaires. These techniques have different strengths and weaknesses. They can be invaluable for identifying problems with draft questionnaires and also for evaluating surveys in the field.
Illustration depicting ovulation and fertilization. Human fertilization is the union of a human egg and sperm, usually occurring in the ampulla of the uterine tube. The result of this union is the production of a zygote cell, or fertilized egg, initiating prenatal development.Scientists discovered the dynamics of human fertilization in the nineteenth century.y convention, gestational age is calculated by adding 14 days to fertilization age and vice versa. In fact, however, fertilization usually occurs within a day of ovulation, which, in turn, occurs on average 14.6 days after the beginning of the preceding menstruation (LMP).
Fertilization happens in the fallopian tube, and the fertilized egg then travels for about 5-6 days down the fallopian tube towards the uterus. Implantation happens when the fertilized egg arrives in the uterus and attaches to the uterine lining.Implantation occurs on average 9 days after ovulation and fertilization, it can happen as early as 6 days after ovulation until 12 days after ovulation.The timing of implantation spotting is within a day or so after implantation, about 9-10 days after ovulation and fertilization.Implantation happens between 6 and 12 days after ovulation, so about 9-10 days after ovulation would be the right time for implantation bleeding and spotting.ertilization happens in the fallopian tube, and the fertilized egg then travels for about 5-6 days down the fallopian tube towards the uterus. Implantation happens when the fertilized egg arrives in the uterus and attaches to the uterine lining.