The chapter reading made the point that you can ALWAYS use z scores to accomplish (1) and (2), but that only in a very specific circumstance can you accomplish (3) with z scores. What is that circumstance? You can use z scores to determine the probability of a score only if the z score is positive. the z score is negative. the population distribution is normally shaped. the population distribution is skewed. If the population distribution of scores is normally distributed, you can use the unit normal table to determine the probability of getting a z score. However, in order to use the table correctly you must know when a problem is asking for a "tail probability" or a "body probability." As indicated in the reading, you should sketch a normal curve, locate the z score, and shade the area under the curve (the probability) that the question is asking for. If the shaded area in your sketch is larger than half of the curve use the _______ of the unit normal table. body column tail column