When a student enrolls in a statistics class, calculating standard deviation is one of the most important skills they can have. This means finding the average of all of the averages in a particular set of data. Although a graphing calculator can easily compute this number, it is important for students to know how to do it on their own.
The first thing that a student needs to do is figure out the average the data set. This is done by adding up all of the averages from each set. Then the resulting number is divided by the number of pieces of data in the set. This is done in the same way that a student would figure out an average for any other math class.
The next step is to subtract the total average from each individual number in the sets. This is how the student will determine the deviance of the numbers. Once they have found the deviances, they must square each of them.
After the square of each deviance has been calculated, all of the squares must be added together. The resulting number is then divided by one less than the number of the set. For example, if there are ten numbers in the set, the result will be divided by nine. The final step in determining the standard deviation is finding the square root of the resulting number.
Of course, it is easier for any student to determine standard deviation with a graphing calculator, but they may not always have a calculator on hand. There are also many standardized tests that do not allow students to use a calculator in order to solve problems. For times like this, it is necessary that every math student knows how to calculate standard deviation without the use of a graphing calculator.
