The answer is 9. Let's first use and example, then view it conceptually. If we have scores of 3, 4, 5, 6, and 7, the mean will be five. (3 + 4 + 5 + 6 + 7)/5 = 25/5 or 5 If we add 4 to each of those scores we will then have: (7 + 8 + 9 + 10 + 11)/5 = 45/5 = 9 To see that this will work for…

None. z-scores are linear transformations that are used to convert an "ordinary" Normal variable - with mean, m, and standard deviation, s, to a normal variable with mean = 0 and st dev = 1 : the Standard Normal distribution.

The advantage of a grouped frequency distribution is that it is small enough for you to get a pretty good idea at a glance how the scores are distributed. The disadvantage is that you are lumping scores together, thus losing some of the information in the original scores.