SUMMATION NOTATION or SUMMATION (Σ) is the most common symbol used in statistics.
In statistics, variables are represented by using capital letters.
Example:
If we want to represent the age of 40 students in a class, the age of the first student is represented by X1, the age of the second student is X2, the age of the third student is X3, and so on until X40. The sum of the ages can be expressed in this way:
Nominal Scale - most primitive level of mesurement; used when we want to distinguish one object from nanother but the amount of difference cannot be determined
Examples:
Gender and nationality are in the nominal scale.
Alive or dead (fish) are also in the nominal scale.
Ordinal Scale - data are arranged in some specified order or rank; we can say that one is better or greater than the other; cannot tell how much more or how much less
Examples:
order of children in a family;
order of 10 fish according to their length (1st, 2nd, 3rd, etc)
Interval Scale - the amount of difference between two data is known or specified
Example:
If John is 35 years old and Ben is only 6 years old, we can say that John is 29 years older than Ben.
Ratio Scale - similar to the interval scale, but always starts from an absolute or zero point; there is always the presence of measure
Example:
If John is 75 kg and Ben is only 25 kg, then we can say that John is three times heavier than Ben or that Ben is three times lighter than John.
Population - large collection fo objects persons, places or things
Examples:
All the residents of the Philippines is considered a population.
All the fish in a lake is considered a population.
Samples - small portion or part of a population; also a subgroup, subset, or representative of a population.
Examples:
10,000 Filipinos is a sample of the Philippine population.
175 fish in a lake is a sample of the fish population in the lake.
Parameter - any numerical or nominal characteristic of a population
Examples:
The age of the selected Filipinos (or even of the whole population) is a parameter.
The length of the fish is a parameter.
1: INTRODUCTION TO STATISTICS
STATISTICS is a scientific body of knowledge that deals with the collection, organization or presentation, analysis, and interpretation of data.
Collection - gathering of information or data
Organization or Presentation - involves summarizing data or information intextual, graphical, or tabular forms
Analysis - involves describing data by using statistical methods and procedures
Interpretation - process of making conclusions based on the analyzed data
Descriptive and Inferential Statistics
Descriptive Statistics is a statistical procedure concerned with describing the characteristics and properties of a group of persons, places or things.
Inferential Statistics is a statistical procedure that is used to draw inferences or information about the properties or characteristics by a large group of people, places, or things or the basus of the information obtained from a small portion of a large group.