Alpha emission in an atom reduces its atomic number by two. An alpha particle is actually the nucleus of a helium-4 atom.   In alpha decay, atomic number decreases by 2, and atomic mass decreases by 4.  .   An alpha particle is two protons and two neutrons, this is the same as a helium nucleus.
On most PraxisÂ® tests, each selected-response question answered. correctly is worth one raw point, and your total raw score is the. number of questions answered correctly on the full test. Selected-. response questions are scored by computer.
It is the standard score or z-score transformation. The standard score transformation is a linear transformation such that the transformed mean and standard deviation are 0 and 1 respectively. The selection of these values was somewhat arbitrary, but not without some reason.