Sampling Error - Rojo Research -- Estimates are based on a probability sampling technique. As a result, the true figures of Rojo Research estimates can lie within a range of + or - the published estimates. Standard Error is calculated by using the formula: 2 standard deviations = 2(√ P(100-P)/n). Where P = cume rating and n = sample size. The following table illustrates the results of this formula. This table is read as follows:Find the vertical column with he percentage closest to the way your results divide. Then find the horizontal row closest to the size of the sample. For example, if your results are at the 20% lever and your sample size is 400, the true figure might be as much as 23.9% or as little as 16.1% (20% plus or minus 3.9%). If the results show 80%, the true figures might be as much as 83.9% or as little as 76.1%. The odds are only 5 times out of every 100 random surveys that the difference between the sample percentage and the surveyed population percentage of either 20% or 80% when these percentages are computed from a random sample base of 400 respondents. ROJO RESEARCH © Copyright 2006. All rights reserved.