Population Vs Sample
What is population?
A population is the whole group that we want to draw conclusions
What is a sample?
A sample is a part of the population, typically it shall represent majority of population
Example:
Weather forecast take data from the sample and predict rain to the whole population
Survey done for small group, the conclusions are drawn to the whole population
Key reasons for using samples:
- Impracticality of getting data points of each population
- Cost effectiveness, time saving of getting data from small group
- Accessibility
Notations used for sample and population
Population:
- N: size of the entire population
- μ (mu): population mean
- σ (sigma): population standard deviation
- π (pi): population proportion
Sample:
- n: size of the sample
- x̄ (x bar): sample mean
- s: sample standard deviation
- p: sample proportion
