MAT3

• STATISTICS as a tool in decision-making
• Statistics from a Latin word “status” which means state
• Statistics. A science (branch of Mathematics) that deals with collection, presentation, analysis, and interpretation of data.
• Division of STATISTICS are Descriptive Statistics and Inferential Statistics
• DESCRIPTIVE STATISTICS. summarizes or describes the important characteristics of a given set of data. It involves the collection, organization, summarization, and presentation of data. It is being applied once the set of data refers to a population or to a sample.
• INFERENTIAL STATISTICS. aims to give information about the population by studying the characteristics of the sample drawn from it. It is the branch of statistics that interprets and draws conclusions from data. It uses hypothesis testing.
• 1. Set - a group or collection of objects or numbers, considered as an entity unto itself.
• Universe (target population) - is the set of all entities under study. The entire group of people or objects to which the researcher wishes to generalize the study findings
• Population (accessible population) – is the set of complete collection or totality of all possible values of the variables. The portion of the universe to which the researcher has reasonable access; may be a subset of the target population (universe). (Group of people, animals, things or ideas to which any conclusion based on characteristics of sample will be applied)
• Sample - a subset or sub-collection or portion of elements drawn from a population.
• Parameter – describes the population, refers to specific characteristic of the population subject of interest or subject of investigation that is measurable.
• Statistic – describe the samples, refers to the charcateristics of the samples
• DATA – a result of experimentation, observation, investigation and other means and often appears as a numerical figure and then evaluated to make it into useful knowledge.
• Statistical Data - Refers to any information concerning to a population or sample
• Classification (Nature) of Data: •Types of data according to SOURCE, FUNCTIONAL RELATIONSHIP, CATEGORIES, Classification of data according to SCALE OF MEASUREMENT
• Data – refers to any information concerning to a population or sample. Pieces of information or facts for reference.
• Variable – refers to the different characteristics of the population or the sample, that continuously varies.
• Primary Data – refer to information which is gathered directly from the original source.
• Secondary Data – refer to information which is taken from a secondary source.
• Independent Data – refer to any controlling data. Data which are not affected by any other data.
• Dependent Data – any data that is affected by controlling data.
• Qualitative Data – uses categories or attributes that are distinguished by some non-numeric characteristics
• Quantitative Data – consist of numbers representing counts or measurements
• Discrete Data – can assume a finite or countable number of vaues. Cannot be represented by fractions or decimal numbers but any whole number only. values obtained by counting
• Continuous Data – can assume infinity of many possible values corresponding to the points on a line interval. values obtained by measuring
• CLASSIFICATIONS OF DATA: NOMINAL, ORDINAL, INTERVAL AND RATIO
• NOMINAL -  data that consists of names, labels, or categories only
• ORDINAL - measurements deal with order or rank, provides   comparison but  the degrees of difference are not available
• INTERVAL - show likeness, differences and give meaningful amounts between data. It does not have a “true zero” starting point,  instead it is arbitrarily assigned
• RATIO - modified interval level to include zero as a starting point
• 5 Steps in Statistical Investigation: Identification of the problem, Collection of Data, Presentation of Data, Analysis of Data and Interpretation of Data
• Methods of Collecting Data: Direct or Interview Method, Indirect or Questionnaire Method, Registration Method, Observation Method and Experiment Method
• Methods of Presenting Data: Textual Form, Tabular Form and Graphical Form
• Textual Form - data is presented in paragraph form
• Tabular Form - data are presented in tables (rows and columns).
• Graphical Form - Data are presented in visual forms.
• Probability. originated from gambling , measure of how likely an event is and describe the level of certainty
• Outcome - a desired measurement or answer obtained after an experiment
• • Sample Space set of all possible outcomes of an experiment
• Event - set of all expected outcomes of an experiment