First, consider deliberate thinking. Deliberate thinking is relatively slow, rule-based and explicit; a contemplative process of weighing pros and cons, gathering scientific or statistical evidence. It would appear that this makes for pretty solid decision-making.
Jul 24, 2015. Outliers increase the standard deviation. Mean is most affected by outliers, since all values in a sample are given the same weight when calculating mean. A value that is far removed from the mean is going to likely skew your results and increase the standard deviation. Say you have five values: 2, 1, 2, 1.5, and 2.1.
By subtracting Q1 from Q3, we get a spread of 1.36 standard deviations for the IQR. Multiply that value by 1.5, add it to Q3 and subtract it from Q1 and you now have a metric for determining outliers. Anything 2.72 standard deviations above Q3 or 2.72 below Q1 is classified as an outlier. You could also say all values that are 3.4 standard deviations above or below the median/mean are outliers. Now, onto how outliers affect the distribution itself. Again, it's pretty simple.