What is statistics?
Example
- Descriptive Statistics: Calculating the average income in a city
- Inferential Statistics: Predicting election outcomes based on sample data
Types of Data
Example
- Discrete: Number of books read in a year
- Continuous: Measuring temperature over time
- Nominal: Types of fruits - apple, banana, cherry
- Ordinal: Customer satisfaction rating - satisfied, neutral, dissatisfied
Sampling Methods
Example
- Simple Random Sample: Drawing random student IDs from a list
- Systematic Sample: Selecting every 10th person on a roster
- Stratified Sample: Dividing by age groups, then sampling from each
- Cluster Sample: Selecting a few schools, then surveying all students in those schools
- Convenience Sample: Asking passersby at a mall for opinions
Sampling error
- Despite random sampling method, there may still be discrepancy between sample result and the actual population result
- This occurs because of chance fluctuations in the sample selection
- Combat this error by taking larger samples
Experimental Design and Ethics
Questions to ask about the source of the study:
- Who is reporting this data?
- Are there conflicts of interest?
- Who is funding the study?
Questions to ask about the statistics:
- Was there a large enough unbiased sample?
- Is the data new and relevant or old and outdated?
- Are complete details of the methods and assumptions provided?
- Was the study peer-reviewed by experts before publication?