Learn how to use a z-score table. Practice Problems for Z-Scores. Calculate the z-scores for the following: Sample Questions. Scores on a psychological well-being scale range from 1 to 10, with an average score of 6 and a standard deviation of 2. What is the z-score for a person who scored 4? Step 1: Find the z-score. First, we will find the z-score associated with a height of 26 inches. z-score = (x - μ) / σ = (26 - 26.5) / 2.5 = -0.5 / 2.5 = -0.2. Step 2: Use the z-table to find the percentage that corresponds to the z-score. Next, we will look up the value -0.2 in the z-table: Z table or the Z-score table also called the standard normal table is a mathematical table used to find the probability that the z-score value is below, above, or between the values on the standard normal distribution. Standard scores are most commonly called z-scores. Suppose you want to find the probability of a Z-score of -2.25 or lower. Step 1: Identify the Z-score as -2.25. Step 2: You are looking for the probability to the left of the Z-score. Step 3: Use the negative Z-table. Step 4: Find the intersection of the row for 2.2 and the column for 0.05. The value is 0.0122. To use the z-score table, start on the left side of the table and go down to 1.2. At the top of the table, go to 0.05. This corresponds to the value of 1.2 + .05 = 1.25. The value in the table is .8944 which is the probability. Roughly 89.44 percent of people scored worse than Zoe on the ACT. Use a z-table to find probabilities corresponding to ranges of z-scores and to find p-values for z-tests. The z-table is divided into two sections, negative and positive z-scores. Negative z-scores are below the mean, while positive z-scores are above the mean. There are two z-score tables which are: Positive Z-score Table: Used when the Z-score is positive and above the mean. A positive Z-score table allows you to find the percentage or probability of all values occurring below a given positive Z-score in a standard normal distribution. The z score table helps to know the percentage of values below (to the left) a z-score in a standard normal distribution. Q2 What are the Types of Z Score Table? There are two z-score tables which are: Positive Z Score Table: It means that the observed value is above the mean of total values. How to Read The Z Table. To map a Z score across a Z Table, it goes without saying that the first thing you need is the Z Score itself. In the above example, we derive that Eric's Z-score is 0.56. Once you have the Z Score, the next step is choosing between the two tables. Use this Z table calculator to easily calculate the Z-score from a given raw score. Also computes areas under the normal curve ( p -values) cut off by a given score. A table of Z scores and corresponding p-values is included, as well as the z score formula. Also calculates Z from p. Calculate Quick navigation: Using the Z score calculator lywcJ7b.