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.
Save. DAJ/amana images/Getty Images. A Z score is a statistical calculation that you can perform on a single data point that belongs to larger data set. The Z score tells you how far -- in standard deviations -- that data point is from the mean, or average, of the data set.ave. DAJ/amana images/Getty Images. A Z score is a statistical calculation that you can perform on a single data point that belongs to larger data set. The Z score tells you how far -- in standard deviations -- that data point is from the mean, or average, of the data set.