MMW (FINALS)

• STATISTICS


  the branch of mathematics that deals with data collection, organization, analysis, interpretation, and presentation
• DATA COLLECTION


  defined as the procedure of collecting, measuring, and analyzing accurate insights for research using standard validated techniques.
• DATA ORGANIZATION


  method of classifying and organizing data sets to make them more useful, it can be applied to physical records or digital records.
• DATA ANALYSIS


  process of inspecting, cleansing, transforming, and modeling data with the goal of discovering useful information, informing conclusions, and supporting decision-making.
• INTERPRETATION OF DATA 


  process of assigning meaning to the collected information and determining conclusions, significance, and implications of findings.
• PRESENTATION OF DATA


  organization of data into tables, graphs or charts, so that logical and statistical conclusions can be derived from the collected measurements.
• Two types of Statistical Methods

  Descriptive Statistics

  Inferential Statistics
• Population


  Consists of the totality of the observation.
• Sample


  Is the part of the population
• Variable


  In any characteristics, numbers, or quantity that can be measured or counted.
• Two kinds of variables:

  Qualitative variables

  Quantitative variables
• Qualitative Variables 


  Categorical variables; variables that are not numerical.

  Describes data that fits into categories.
• Quantitative variables 


  Are numerical. It can be ranked and has order.
• Quantitative variables can be classified;

  Discrete variables

  Continuous variables
• Discrete Variables 


  A variable whose value is obtained by counting.
• Continuous variables 


  Can assume an infinite number of values between any two specific values.

  Obtained by measuring.

  Include fractions and decimals.
• Types of Statistical Data

  Numerical

  Categorical
• Four Levels of Measurement

  Nominal

  Ordinal

  Interval

  Ratio
• Nominal 


  Deals with names, categories, or labels.

  Without quantitative value.
• Ordinal


  Ordered but no difference between the data.

  (Order of values)
• Interval


  Data that can be ordered, and in which differences between the data does make sense.

  No starting point

  (Fahrenheit and Celsius, example)
• Ratio


  Highest level of measurement.

  Presence of a zero, absolute zero.
• Common Methods of collecting data:

  In-person interviews

  Mail Surveys

  Phone Surveys

  Web/Online Surveys
• Cons of survey method

  • Expensive
  • Data collection errors
  • Lag time
• Phone Surveys


  Pros: High degree of confidence on the data collected, reach almost anyone

  Cons: Expensive, cannot self-administer, need to hire an agency
• Web/Online Surveys


  Pros: Cheap, can self-administer, very low probability of data errors

  Cons: Not all your customers might have an email address/be on the internet, customers may be wary of divulging information online
• Three Ways of Presenting Data

  • Textual
  • Tabular
  • Graphical
• Textual


  Data presentation with the help of a paragraph or a number of paragraphs
• Tabular


  Presenting data using the statistical table. A systematic organization of data in columns and rows
• Graphical


  A chart representing the quantitative variations or changes of variables in pictorial or diagrammatic form
• Frequency Distribution


  Frequency is the rate that measures how often something occurs
• Frequency


  The number of times something occurs
• Frequency Distribution Table


  1. Put numbers in order

  2. Count how often each number occurs
• Frequency Distribution Table(counting frequencies)


  • 1 occurs 2 times
  • 2 occurs 5 times
  • 3 occurs 4 times
  • 4 occurs 2 times
  • 5 occurs 1 time.
• Bar Graph


  • Pictorial representation of statistical data where length of rectangles represents proportional value
  • Used to compare values of several variables
  • Applicable to discrete categories only
• Line Graph


  • Graphical display of information that changes continuously over time
  • Points connect data to show continuous change
  • Lines can descend and ascend based on data
  • Can compare different events, situations, and information
• Pie Chart


  • Circular graph where pieces are proportional to the fraction of the whole in each category
  • Each slice represents the size of that category in the group as a whole
  • The entire "pie" represents 100 percent of a whole
• Measures of central tendency


  Values that identify the "center" of a set of data
• Measures of central tendency

  • Mean
  • Median
  • Mode
• Mean


  The most common measure of central location, obtained by getting the sum of all values of the observations divided by the number of observations