Is it true that black people with o blood type are half white?

There is no scientific basis for the claim that black people with O blood type are half white. Blood type is determined by the presence or absence of certain antigens on the surface of red blood cells. The O blood type simply means that a person's red blood cells lack both the A and B antigens, but race or ethnicity is determined by a person's genetic makeup, which includes a combination of various genetic factors.