With our z-score of 0.25, we now head to the z-table to find the area associated with it. When you split a distribution into two parts, the smaller portion is the tail, while the larger portion is the body. This z-table (normal distribution table) shows the area to the right hand side of the curve. Use these values to find the area between z0 and any positive value. Z is the standard normal random variable. The table value for Z is the value of the cumulative normal distribution at z. This is the left-tailed normal table.

There is a table which must be used to look up standard normal probabilities. The z-score is broken into two parts, the whole number and tenth are looked up along the left side and the hundredth is looked up across the top. Defining the standard score (z-score) and further help on calculations involving the standard score (z-score). To do this, we refer back to the standard normal distribution table. In this table are a bunch of z-scores and proportions for the Standard Normal Distribution (which is the z-score standarized Normal distribution; N(0,1)).

The table gives these two proportions for selected z-score values. Column B gives the proportion in body, and Column C gives the proportion in tail. A table of the standard normal distribution gives us the probability between any two z scores. This probability is the area under a curve. If you need help reading the table, begin with the value of your z score. In order to use this particular table, the value should be rounded to the nearest hundredth.