Calculate the percentage of scores both above and below your z-score by using a table with a picture of one bell shaped curve with both the lower tail left side and the upper tail right side shaded Table Two in Resource 3. This looks like a large plus sign. Subtract each individual score from the mean.
Calculate the percentage of scores either above or below your z-score by looking up the z-value in the one-tailed z-table, such as Table One in Resource 3. For z-score 0.
Ignore the - sign. If you plot everyone's score, you will see that the shape resembles a bell curve -- called the normal distribution in statistics.
If you have a score of 12, subtract this from the mean Again, ignore the negative sign and look up the value 0. Ignore the negative sign. If your data fit a normal distribution, you can convert the raw score to a z-score and use the z-score to compare your standing to everyone else's in the group.
Multiply this value byshowing that 59 percent of the test scores were lower than All of the area below that z-score will be shaded, indicating this table is for looking up scores up to a particular z-score.
Tables of this type will show two bell-shaped curves, with the number below a z-score shaded on one curve and the number above a z-score shaded in the second bell curve. Make sure your data are normally distributed.