The 32-week biparietal diameter standard says a standard for the size of the distance between the biparietal diameter of the fetal head at 32 weeks of pregnancy, generally the mean of the biparietal diameter at 32 weeks is at 8.17cm, which means that most people are at 8.2cm, 8cm more, which is the biparietal diameter, said the mean, which is the average, most people average at this size. Of course it is actually a range, because some people are fat and some people are thin, some children are big and some children are small. 8.17cm is the mean, the average of most people, but in fact it is a range, that is, how much to how much, we are talking about a standard deviation is 8.17 plus one sd and minus one sd between a range, the average of the population is 8.17cm, 32 weeks for the biparietal diameter.