If the range is smaller the set of data will have a low standard deviation. If the numbers have a large range, or the difference between the largest and smallest value, then it will have a high standard deviation. The standard deviation is a measure of the amount of variation in a set of values. A z-score is a way to compare a raw score or data point to the mean, or the average, by using standard deviations. One of the ways that this is done is by the use of the z-score. In the world of statistics, numbers and data are gathered, organized and compared in order to derive information and patterns. The Z score itself is a statistical measurement of the number of standard deviations from the mean of a normal distribution. In other words, Z tables help compare data points within a group and show what percentage they are above or below the group average.
Z-tables help graphically display the percentage of values above or below a z-score in a group of data or data set. Definition: A Z-Score table or chart, often called a standard normal table in statistics, is a math chart used to calculate the area under a normal bell curve for a binomial normal distribution.
