MMW

• Statistics is the science of collecting, organizing, summarizing, and analyzing information to draw conclusions or answer questions.
• Data are "factual information used as a basis for reasoning, discussion, or calculation. - Merriam Webster dictionary
• The group to be studied is called the population.
• Universe is the set of all entities under study
• Population is the set of all possible values of the variable.
• An individual is a person or object that is a member of the population being studied.
• Process of Statistics - 1. Identify the research objective 2. Collect the information needed to answer the questions 3. Organize and summarize the information 4. Draw conclusion from the information
• Sample is a subset of the universe or the population
• Descriptive statistics describe the information collected through numerical measurements, charts, graphs, and tables.
• The main purpose of descriptive statistics is to provide an overview of the information collected.
• Inferential statistics uses methods that takes results obtained from a sample, extends them to the population, and measures the reliability of the result.
• If the entire population is studied, then inferential statistics is not necessary.
• Variables are the characteristics that differentiate every individual within the population/sample.
• Classification of Variables - qualitative variables and quantitative variables
• Qualitative variable is variable that yields categorical responses.
• Quantitative variable takes on numerical values representing an amount or quantity
• Gender - qualitative variable
• Temperature - quantitative variable
• Number of Children - quantitative variable
• Hair color - qualitative variable
• Zip code - qualitative variable
• Discrete variable is a quantitative variable that either a finite number of possible values or countable number of possible values.
• The term countable means that the values result from counting, such as 0, 1, 2, 3, and so on.
• Continuous variable is a quantitative variable that has an infinite number of possible values that are not countable.
• Levels of Measurement - nominal, ordinal, interval, ratio
• Nominal Level - identify, name, classify, or categorize objects or events.
• Ordinal Level - like nominal scale but have an additional property of a logical or natural order to the categories or values.
• Interval Level - identify, have ordered values, and have the additional property of equal distances or interval between scale.
• Ratio Level - identify, order, represent equal distances between scores values, and have an absolute zero point.
• Ranking of college athletic teams - ordinal
• Employee number - nominal
• Number of vehicles registered - ratio
• Brands of soft drinks - nominal
• Number of car passers along C5 on a given day - ratio
• Data collection is the process of gathering and measuring information on variables of interest, in an established systematic fashion that enables one to answer stated rs qs, test hypothesis, and evaluate outcomes.
• Consequences from improperly collected data

  1.) inability to answer rs qs accurately

  2.) inability of repeat and validate the study

  3.) distorted findings resulting in wasted resource

  4.) misleading other researchers to pursue fruitless avenues of investigation

  5.) compromising decisions for public policy

  6.) causing harm to human participants and animal subjects
• Sources of data - primary and secondary data
• Steps in data gathering:

  1.) Set the objectives for collecting data

  2.) Determine the data needed based on the set objectives

  3.) Determine the method to be used in data gathering and define the comprehensive data collection points

  4.) Design data gathering forms to be used

  5.) Collect data
• Primary Data - include information collected and processed directly by the researcher
• Secondary data - information that has already been collected, processed and reported out by another researcher/entity