Statistics
There are numerous statistical analyses which can be executed on data sets. In MATLAB software, the statistical functions are in the data analysis help topic known as datafun.
In common, we will write a data set of n values as
x ={x_{1}, x_{2}, x_{3}, x_{4}, . . . ,x_{n}}
In MATLAB, this will usually be represented as a row vector known as x.
The Statistics can be used to characterize the properties of a data set. For illustration, consider a set of exam grades {33, 75, 77, 82, 83, 85, 85, 91, 100}. What is a "normal", or "average" or "expected", exam grade? There are many ways that this could be interpreted. Perhaps the most general is the mean grade that is found by summing the grades and dividing by the number of them (the answer would be 79). The other way of interpreting that would be the grade found the most frequent, that would be 85. The value in the middle of the list, 83, could also be used. The other property which is useful to know is how spread out the data values is in the data set.
This part will cover several simple statistics, as well as set operations which can be executed on data sets. A few statistical functions need that the data set be sorted; therefore sorting will also be covered. By using index vectors is a way of representing the data in order, with no physically sorting of the data set. Lastly, searching for values within a data set or database is also helpful.