A type of frequency polygon that is unimodal (one single mode/peak) The mean, median and mode are all the exact same value. Distances along the horizontal axis of the distribution, when measured in standard deviations from the mean, always encompass the same proportion of total area under the curve. The distance from any given point to the mean is exactly the same. To find a percentage of the total area above, below or between scores must first be. Z-scores have the same values for their mean (0) and standard deviation (1) Raw units (iq, cm, dollars etc. ) are converted to z-scores o. This process is the same as changing miles to km etc. The formula for converting original scores to z-scores in a sample is. If xbar = 30 and s = 14. 14. A zscore of 1. 00 indicates that the original score lies one standard deviation above the mean.