A Z-table, also known as a standard normal table, is a mathematical table used in statistics to determine the probability of a standard normal random variable. It provides the area (or probability) to the left of a given Z-score, which represents how many standard deviations a data point is from the mean in a standard normal distribution. Z-scores are calculated by subtracting the mean from a data point and then dividing by the standard deviation. The Z-table helps researchers and statisticians understand the distribution of data, making it easier to interpret results in various fields, including psychology, finance, and quality control.