**Mean**:

The mean is the sum of scores divided by the number of scores.

where is the number of scores.

**Mode:**

Mode of a set of data is the value in the set that occurs most often.

**Range:**

The range of a set of data is the difference between the highest and lowest values in the set.

**Variance:**** **

The variance of a sample measures how the conservations are spread around the mean.

**Standard Deviation:**

The standard deviation is the square root of the average of the squared deviations from the mean (variance).

**Categorical frequency distributions:**

Categorical frequency distributions can be used for data that can be placed in specific categories, such as nominal- or ordinal-level data.

**Central Limit Theorem:**

As the sample size increases the sampling distribution of the sample mean approaches the normal distribution with mean and variance .

**The exponential, binomial, and normal density functions:**

The exponential, binomial and normal density functions are used along with their respective probability distributions to approximate statistical models and values.