1. This lesson is on using the z-table to find percentages. As we have learned in class you will be given
information either as a data set or as calculated statistics that you will use in the z-score formula. In tis
example the mean and standard deviation have been given to you as well as a data point to use.
Identify the three pieces of information and substitute them into the formula. Round your answer to the
nearest hundredth. You may stop the slide show while you find the z-score. You will need it for the
next step.
Now that you have the z-score we need to find the percent of the data the question is asking for. Since
the value is a negative number we need the page of negative z-scores. Find the first two digits of your
answer down the left hand side of the table. Find the third digit across the top of the table. The answer
you are seeking lies in the intersection of the row and column. This is the proportion od data that lies
below the given value. You may write the answer in the form of a percent.