**Z SCORES**
**Data with different values are better compared by converting to a common measure. The common measure used is the distance from the mean in terms of standard deviation. This is done by way of "Z" scores. Each value is converted to standard deviations with the following formula:**
** Z = (X-AVG)/STD**
** Where:**
** X = the data to be converted**
** AVG = mean for the data group**
** STD = standard deviation for the data group**
**The Z scores for the Summerton data are:**
**TABLE**
** DATA Z SCORES**
** 250 -1.071**
** 300 -0.913**
** 350 -0.755**
** 350 -0.755**
** 400 -0.597**
** 400 -0.597**
** 400 -0.597**
** 450 -0.440**
** 450 -0.440**
** 450 -0.440**
** 500 -0.282**
** 500 -0.282**
** 600 0.033**
** 650 0.191**
** 700 0.349**
** 750 0.507**
** 1000 1.295**
** 1200 1.926**
** 1500 2.873**
**Z scores can be used to directly compare two sets of data even though there may be differences **

in magnitude between the two. They will be used to transform raw data in subsequent statistical

**measures as the transformed data allows the easy calculation of a number of otherwise complex; statistics.**

**DIAGRAM **
**WHEN THE DATA IS SKEWED, THE 3 MEASURES CANNOT COINCIDE**