01-25-2012

Statistics – The art and science of collecting, analyzing, presenting and interpreting data.

Descriptive statistics – Quick mathematical summary of the data (mean, median, mode, range, variance, standard deviation)

Observational Unit (element) – Object (person or thing) we are collecting data on or about.

1. Variable – Characteristic of an observational unite that could change from one unit to the next.
1. Quantitative Variables – Numeric in nature. Usually based on some type of measurement or number.
2. Categorical (Qualitative) Variables – Grouping into categories (e.g. gender, eye color, hair color)
1. Binary – Subset of categorical where there are only two possible variables (e.g. gender)

2. Population – Refers to all possible observational units. (100% accuracy only comes from a population)
1. Parameter – Numerical characteristic about a population

3. Sample – Small group of the population.
1. Statistic – Numerical characteristic about a sample. Statistics are used to make predictions about a population