Chapter 1
Statistic: Descriptive measure of a sample. Usually represented by Roman letter
: sample mean : sample variance : sample standard deviation
Sample
A portion or subset of the population. (Caution: Sample must be large enough to represent the whole.)
Parameter
Descriptive measure of the population. Usually represented by Greek letters.
Branches of Statistics
Descriptive statistics, Inferential statistics
Census
Gathering data from the entire population
σ2(sigma squared)
population variance
Ratio Level Data
Ratio data have the same properties as interval data, but ratio data have an absolute zero, and the ratio of two numbers is meaningful. e.g. height, weight, time, volume, distance, # of people, age, Profit and Loss, Revenue, Expenses, Financial ratios (P/E Ratio, Inventory Turnover, Quick Ratio)
Population
The whole collection of persons, objects, or items under study
Accounting
auditing and cost estimation
Finance
investments and portfolio management
Economics
regional, national, and international economic performance
Parametric Statistics
require that data be interval or ratio.
Classify each of the following as nominal, ordinal, interval, or ratio data. a. The ranking of a company by Fortune 500 -- ordinal b. The number of tickets sold at a movie theater on any given night -- ratio c. The identification number on a questionnaire -- nominal d. Per capita income -- ratio
INFO
Nominal data are the most limited data in terms of the types of statistical analysis that can be used with them. Ordinal data allow the researcher to perform any analysis that can be done with nominal data and some additional analyses. With ratio data, a statistician can make ratio comparisons and appropriately do any analysis that can be performed on nominal, ordinal, or interval data. Some statistical techniques require ratio data and cannot be used to analyze other levels of data.
INFO
Nonparametric Statistics
If the data are nominal or ordinal, nonparametric statistics must be used. Nonparametric statistics can also be used to analyze interval or ratio data.
Statistical techniques can be separated into two categories
Parametric Statistics, Nonparametric Statistics
Statistics
a science dealing with the collection, analysis, interpretation, and presentation of numerical data
Nominal Level Data
can be used only to classify or categorize. The categories can be numbered, but no ordering of the cases is implied. e.g. gender, religion, ethnicity, ethnicity, political affiliation, geographic location, place of birth, job, SS#, telephone numbers, ZIP codes.
Ordinal Level Data
can be used to rank or order object. e.g. The instructor displayed a personal interest in students and their learning. 1 = Hardly Ever, 2 = Occasionally, 3 = Sometimes, 4 = Frequently, 5 = Almost Always e.g. Position within an organization 1 for President, 2 for Vice President, 3 for Plant Manager, 4 for Department Supervisor, 5 for Employee
Management
human resources, compensation, and quality management
Interval Level Data
if the data are always numerical and the distances between consecutive numbers are equal. And, location of origin(zero) is arbitrary. e.g. Fahrenheit Temperature and Celsius Temperature (Note: Zero degree is just another point on the scale and does not mean the absence of the temperature)
Marketing
market analysis and consumer research
International Business
market and demographic analysis
Management Information Systems
performance of systems which gather, summarize, and disseminate information to various managerial levels
μ (mu)
population mean
σ(sigma)
population standard deviation