Figure 2 illustrates a normal distribution of test scores with a mean of 100 and a standard deviation of 15. The standard deviation is an indication of the variability of scores in a population (Mather & Jaffe, 2002).nderstanding Standard Scores. The major purpose of standard scores is to place scores for any individual on any variable having any mean and standard deviation on the same standard scale so that comparisons can be made.
Note: True symptoms of PMS do not begin until after Day 13, any symptoms you experience earlier in your cycle may have another cause. However, you should still include any symptoms you experience on Days 1 to 13 on your menstrual cycle calendar.
Onset of PLS usually occurs spontaneously after age 50 and progresses gradually over a number of years, or even decades. The disorder usually begins in the legs, but it may start in the tongue or the hands.Symptoms may include difficulty with balance, weakness and stiffness in the legs, and clumsiness.nset of PLS usually occurs spontaneously after age 50 and progresses gradually over a number of years, or even decades. The disorder usually begins in the legs, but it may start in the tongue or the hands.