An analogous formula applies to the case of a continuous probability distribution. Not every probability distribution has a defined mean; see the Cauchy distribution for an example. Moreover, for some distributions the mean is infinite: for example, when the probability of the value is for n = 1, 2, 3, ....
Red blood cell (RBC) production (erythropoiesis) takes place in the bone marrow under the control of the hormone erythropoietin (EPO). Juxtaglomerular cells in the kidney produce EPO in response to decreased O 2 delivery (as in anemia and hypoxia) and increased levels of androgens.
To: jan945. Hi. The cellular components of blood (red cell, white cell, platelets) are produced in the bone marrow. If your dad's doctor said that his body is no longer producing blood, he most likely has something wrong in his bone marrow, which prevents it from producing blood. Various conditions can result in bone marrow injury/ destruction. Cancer (e.g. leukemia or lymphoma) can directly invade and destroy bone marrow cells.