Final answer:
Becky's Hct may be below the normal range due to aplastic anemia. Mark's should be within the normal range despite exercise, and both Susan and John's Hct could be slightly elevated due to living at a high altitude and engaging in regular intense exercise.
Step-by-step explanation:
The hematocrit (Hct), also called packed cell volume (PCV), is a measure of the percentage of red blood cells (RBCs), or erythrocytes, in a blood sample. This is an important test that can indicate various health conditions related to blood composition.
a. Expected Hct for Becky: Since Becky is undergoing treatment for chronic leukemia which has caused aplastic anemia, her RBC count is likely lower than normal, because aplastic anemia is a condition where the body doesn't produce enough new blood cells. Therefore, her Hct would be expected to be below the normal range for a female, which is 37-47%.
b. Expected Hct for Mark: Being healthy and living at a lower altitude means Mark's Hct should be within the normal male range (42-52%). However, since Mark exercises regularly and engages in strenuous physical activity such as running, there could be transient increases in his Hct but generally, it should remain within the normal range.
c. Expected Hct for Susan: Susan, a visitor from Colorado, is accustomed to living at a higher altitude, where oxygen levels are lower. Therefore, her body would have compensated by producing more RBCs, a condition known as polycythemia, which is normal for people living at high altitudes. Thus, her Hct could be slightly elevated, but still within the high-normal range for females.
d. Expected Hct for John: Like Susan, John is from Colorado and also engages in regular intense exercise. Therefore, similar to Susan, his Hct is likely to be on the higher side of the normal range for males.