Statical Methods 15th March Summary Note

What is Statistics?

Statistics is a way of collecting, organizing, and understanding numbers or information. It helps people make decisions based on facts instead of guessing.

Basic Terms in Statistics

1. Variables and Constants

   • A variable is something that changes. Example: A person's height, weight, or age.
   • A constant is something that stays the same. Example: The number of hours in a day (24).

2. Types of Variables

   • Quantitative (Numbers-based): Things that can be measured, like height, weight, or test scores.
   • Qualitative (Category-based): Things that describe groups, like gender, marital status, or nationality.

3. Different Kinds of Quantitative Variables

   • Discrete: Whole numbers only (Example: Number of students in a class).
   • Continuous: Can have fractions or decimals (Example: A person's weight).

4. Dependent and Independent Variables

   • Independent Variable: Something that is changed or controlled in an experiment (Example: Different teaching methods).
   • Dependent Variable: The result that changes because of the independent variable (Example: Students' test scores).

5. Other Variables

   • Confounding Variables: Extra factors that can affect results (Example: A student’s motivation affecting test scores).

6. Data

   • Information collected in numbers or categories (Example: Test scores of students).

7. Population and Sample

   • Population: The whole group being studied (Example: All students in a country).
   • Sample: A smaller group selected from the population (Example: Students from one school).

8. Parameter vs. Statistic

   • Parameter: A fact about the whole population (Example: Average height of all students in a country).
   • Statistic: A fact about a sample (Example: Average height of students in one school).

In short, statistics is about using numbers and facts to understand things better and make better decisions!