Statistics
the science of collecting, organizing, summarizing, an analyzing information to draw conclusions or answer questions. In addition, statistics is about providing a measure of confidence in any conclusions.
Statistic
a numerical summary of a SAMPLE.
Parameter
a numerical summary of an ENTIRE POPULATION.
Descriptive Statistics
organizing and summarizing data through numerical summaries, tables, and graphs.
Qualitative Variable
allow for classification of individuals based on some ATTRIBUTE OR CHARACTERISTIC.
Quantitative Variable
provide NUMERICAL MEASURES of individuals. Arithmetic operations such as addition and subtraction can be performed on the values of a quantitative variable and will provide meaningful results. (
Inferential Statistics
uses methods that take a result from a sample, extend it to the population, and then measure the reliability of the result.
Process of Statistics
1. Identify Research Objective - determine questions the researcher wants answered.
2. Collect the data needed to answer the question(s) posed in the research objective.
3. Describe the data - obtaining descriptive stats and an overview of the data to pro
Examples of Qualitative Variables
Gender, Zip Code (although numerical it describes a region of a state, and cannot be altered mathematically to make sense), TV Brand, etc.. anything that describes a QUALITY.
discrete variable
a quantitative variable that has either a finite number of possible vaues or a countable number of possible values. COUNTABLE = the values result from counting like 0,1,2,3 and so on.
continuous variable
a quantitative variable that has an infinite number of possible values that are not countable.
nominal level of measurement
QUALITATIVE - if the values of the variable name, label or categorize. The naming scheme does NOT allow values of the variable to be arranged or ranked. (e.g.: Gender cannot be ranked by any means)
ordinal level of measurement
QUALITATIVE - if tit has the properties of NOMINAL level of measurement and the naming scheme DOES ALLOW for the values of the variable to be ARRANGED or RANKED. (e.g.: Letter grades can be ranked, but are still qualitative)
interval level of measurement
QUANTITATIVE - if it has the properties of ordinal level of measurement and the differences in the values have meaning. A value of 0 in this level DOES NOT mean the absence of the quantity. (e.g.: 0 Farenheit does not mean NO heat) ADDITION and SUBTRACTIO
Ratio level of measurement
QUANTITATIVE - if it has the properties of interval level of measurement and the RATIOS of the values mean something. A value of zero in the interval level DOES have significance - means there's NONE (absolute zero)! MULTIPLICATION and DIVISION can be log
Population vs. Sample
Population is the ENTIRE group on individuals to be studied whereas Sample is a select group (subset) of individuals.