# Difference between sample regression and population regression line?

## Answer

A sample is a subset of a population. Usually it is impossible to test an entire population so tests are done on a sample of that population. These samples can be selected so that they are representative of the population in which cases the sample will have weights, strata, and clusters. But usually people use random samples. So it's not that the line is different, it's that the line comes from different data. In stats we have formulas that allow a sample to represent a population, if you have the entire population (again unlikely), you wouldn't need to use this sample formulas, only the population formulas.

### Population Regression Function vs Sample Regression Function?

1. PRF is based on population data as a whole, SRF is based on Sample data 2. We can draw only one PRF line from a given population. But we can Draw one SRF for one sample from that population. 3. PRF may exist only in our conception and imagination. 4. PRF curve or line is the locus of the conditional mean/ expectation of the independent variable Y for the fixed variable X in a…

### What is the similarities between population and sample?

Similarity: Both are counts of people/animals/things. Difference: Population is the total # of things, while sample is the # of things that you gather data on. If you pick the right sample size, you can be pretty confident that the results of the sample data is the same as the results of the entire population.

### What is the difference between population survey and sample survey?

A population survey, better known as a census, entails the collection of each unit in the population. In sample survey information is collected from a subset of the population. The subset, or sample, needs to be selected carefully so that it is representative of the whole population and, if that requirement is met, statistics based on the sample are good estimators for the corresponding population parameters.