## Information

Target: Calculate average, standard deviation, the sample size for several variables. Present histogram chart and average range chart

As you may see in the

**Sum of squared** chart,The outliers may influence

**dramatically** the standard deviation result! as you may see in the sum of squares chart. It is

**not recommended** to exclude outliers unless you know the reason for the outliers.

## Statistics

**n** - Number of values

**Mean**- The average

**S**- Sample Standard Deviation, if the list of values you entered is only a sample from the entire population, this is the best estimation for the Population Standard Deviation

**S**^{2}- Sample variance, if the list of values you entered is only a sample from the entire population, this is the best estimation for the Population Variance

**σ**- Population Standard Deviation, if the list of values you entered is the entire population, this is the exact Standard deviation

**σ**^{2}- Population Variance, if the list of values you entered is the entire population, this is the exact Variance

## R Code

The following R code should produce the same results except for the skewness. The 'PerformanceAnalytics' package uses a different methods for skewness calculations.