Sampling is the process of selecting a representative subset of a population to gather information about the entire population.

Systematic sampling involves selecting every kth element from a population, where k is a fixed interval determined by dividing the population size by the desired sample size.

In stratified sampling, the population is divided into homogeneous subgroups called strata, and a sample is selected from each stratum.

Cluster sampling involves selecting a random sample of clusters from a population and then selecting all elements within the chosen clusters.

In simple random sampling, each element in the population has an equal chance of being selected, so the probability of selecting a specific element is 1/N.

Probability sampling involves selecting a sample based on the probability of each element being chosen, ensuring that every element in the population has a known chance of being included in the sample.

A sample is a subset of a population, selected to represent the characteristics of the entire population.

The main purpose of data collection in statistics is to gather information about a population, such as its characteristics, trends, and patterns.

An interview is a data collection method that involves asking respondents a series of questions, either in person, over the phone, or through video conferencing.

A sample survey collects data from a subset of the population, while a census collects data from the entire population.

A pilot study is conducted to test the feasibility of a research study, assess the effectiveness of data collection methods, and identify potential problems before conducting the main study.

Observation is a data collection method that involves observing and recording the behavior of individuals or groups in their natural settings.

Primary data is collected directly from the source, while secondary data is collected from existing sources, such as books, articles, and databases.

A questionnaire is a data collection method that involves sending a set of questions to respondents to be answered in writing.

A sampling frame is a list or database of all the elements in the population of interest, from which a sample can be selected.