NOTES STUDY GUIDE WITH HIGH-YIELD REVISION NOTES,
WORKED EXAMPLES, PRACTICE QUESTIONS, DETAILED
ANSWER EXPLANATIONS, DESCRIPTIVE AND INFERENTIAL
STATISTICS CONCEPTS, DATA ANALYSIS TECHNIQUES,
PROBABILITY FUNDAMENTALS, AND COMPLETE
STATISTICS EXAM SUCCESS TOOLKIT | UPDATED FOR
2026/2027 | LATEST EDITION
1. What is Statistics?
Definition
Statistics is the science of collecting, organizing, analyzing, interpreting, and
presenting data in order to make informed decisions.
Statistics helps people understand information and make predictions or conclusions
based on evidence rather than guesswork.
Importance of Statistics
Statistics is used in:
• Business (market research, sales forecasting)
• Medicine (testing new drugs)
, • Education (analyzing student performance)
• Government (population censuses)
• Agriculture (crop yield studies)
• Sports (player performance analysis)
Example
A company wants to know whether customers like a new product. They collect
information from customers, analyze it, and make decisions using statistics.
2. Data
Definition
Data consists of information collected from:
• Observations
• Measurements
• Counts
• Responses
Data is the raw material upon which statistical analysis is performed.
Examples
, Situation Data Collected
Classroom Students' test scores
Hospital Patients' blood pressure
Election Number of votes
Business Monthly sales
Importance of Data
Without data, statistical analysis cannot be performed.
3. Population
Definition
A population is the complete collection of all outcomes, responses, measurements,
or counts that are of interest.
Characteristics
• Includes every member of interest.
• Usually very large.
• Studying an entire population can be expensive and time-consuming.
Examples