MATH Elementary Statistics

Salary – Company A

Salary – Company B

Salary – Company A

Salary – Company B

Same Company!!

Definitions Statistics – (plural) is a synonym for “numerical facts” Statistics – (singular) is the body of principles and procedures developed for the collection, classification, summarization, interpretation, and communication of numerical data, and for the use of such data Descriptive Statistics – is the part of statistics that encompasses the procedures of data collection, classification, summarization, and presentation Statistical Inference – is the part of statistics that involves procedures for drawing conclusions about a population when the data comprise a sample selected from the population

Definitions (cont) Population (or universe) – is a collection of data containing every item connected to the variable under investigation Sample – is a collection of data constituting only a part of a population Census – is a list of all the items in a population Parameter – is a numerical characteristic of a population Statistic – is a numerical characteristic of a sample

Types of Data Qualitative Data – consist of attributes, labels, or non-numerical entries Quantitative Data – consist of numerical measurements or counts

Types of Data Nominal Level of measurement consists of names, labels, categories. (ie gender, ethnicity, etc.) Ordinal Level of measurement consists of data which can be ordered, but differences between data values have no meaning. (ie good, better, best) Interval Level of measurement is an ordinal level where the differences are meaningful, but there is no zero starting point. (ie temperature, IQ) Ratio Level of measurement is an interval level with a meaningful zero. (ie height, weight)

Types of Data Discrete data – number is either finite or “countable” Continuous data – infinitely number of possible values

Data Description To describe data, three pieces of information should be presented 1.The size of the sample 2.The measure of central tendency 3.The measure of variability

Data Description