Statistics

Fundamentals and Applications

Classifications

DESCRIPTIVE STATISTICS

it is the process of organizing data effectively with the aid of graphical or textual presentation

Classification

INFERENTIAL STATISTICS

Statistics concerned about making intelligent guesses about future events based on existing data

- Concerned with obtaining information about the characteristics of a population based on some sample

Population – the collection of all elements of interest being studied

Sample – a subset of a population

Data – facts that are collected, organized and analyzed.

Variable – Characteristic of the subject being studied. Examples: height, weight, name, sales, student number, etc.

What are the variables presented in the table?

Classification of Variables

Independent Variable – characteristics that influences an outcome, or influences the outcome of another variable.

Dependent variable – a characteristic which is affected or influenced by another characteristic

What is the dependent variable?

What are the independent variables?

Scales of Measurement

• Nominal Scale – characteristics that serve as LABELS for identification

Scales of Measurement

Ordinal Scale – characteristics that has the function of a nominal data but such characteristics can be ranked

Scales of Measurement

Interval Scale – measurements that maintain the characteristics

of an ordinal dataIntervals of observation can be expressed in

terms of a fixed measureArithmetic operations can be applied to such

measurements

Scales of Measurement

Ratio scale – measurements that have the following characteristics

They can be rankedRatio between two observed values yield a

meaningful informationA Zero measurement means NONE

Scales of Measurement

Classification of Data/Variable

Numeric and Non-numeric data (Quantitative and non quantitative data)

Continuous Variables and Discrete Variables

Data Collection (How are data collected)

Surveys (sample surveys)Existing collection of data (obtain data from data

which are already collected)Experimental studies (conduct experiments)Observational studies ( Observe the subject

without influencing them)

Sampling Techniques

Random Sampling – a sampling where every member of the population has an equal chance of being included in the sample.

- Drawing lots- Table of random numbers- Systematic sampling- Stratified random sampling

Sampling Techniques

Non-Random SamplingVolunteer samplingJudgement sampling (targeted sampling)Convenience sampling