# Statistics is the study of the collection Essays

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1. Statistics is the study of the collection, analysis, interpretation, presentation, and organization of data.
2. The entire group of individuals to be studied is called the population
3. An individual is a person or object that is a member of the population being studied.
4. In statistics and quantitative research methodology, a data sample is a set of data collected and/or selected from a statistical population by a defined procedure.
5. A statistic (singular) is a single measure of some attribute of a sample. It is calculated by applying a function (statistical algorithm) to the values of the items of the sample, which are known together as a set of data.
6. Descriptive statistics is the discipline of quantitatively describing the main features of a collection of information, or the quantitative description itself.
7. Inferential statistics uses methods that take a result from sample, extend it to the population, and measure the reliability of the result.
8. A parameter is a number that summarizes some attribute of a population
9. Qualitative, or categorical, variables allow for classification of individuals based on some attribute or characteristic.
10. Quantitative variables provide numerical measures of individuals. Arithmetic operations such as addition and subtraction can be performed on the values of a quantitative variable and will provide meaningful results.
11. A discrete variable is a quantitative variable that has either a finite number of possible values or a countable number of possible values. The term countable means that the values result from counting, such as 0, 1, 2, 3, and so on.
12. A continuous variable is a quantitative variable that has an infinite number of possible values that are not countable.
14. An observational study measures the value of the response variable without attempting to influence the value of either the response or explanatory variables.
That is, in an observational study, the researcher observes the behavior of the individuals in the study without trying to influence the outcome of the study.
Cross-sectional Studies- These are observational studies that collect information about individuals at a specific point in time or over a very short period of time.
Case-control Studies-These studies are retrospective, meaning that they require individuals to look back in time or require the researcher to look at existing records. In case-control studies, individuals that have a certain characteristic are matched with those that do not
Cohort Studies-A cohort study first identifies a group of individuals to participate in the study (the cohort). The cohort is then observed over a period of time. Over this time period, characteristics about the individuals are recorded and some individuals in the study will be exposed to certain factors (not intentionally) and others will not. At the end of the study the value of the response variable is recorded for the individuals.
15,16,17. Confounding in a study occurs when the effects of two or more explanatory variables are not separated. Therefore, any relation that may exist between an explanatory variable and the response variable may be due to some other variable or variables not accounted for in the study
18. A lurking variable is an explanatory variable that was not considered in a study, but that affects the value of the response variable in the study.
19. A sample of size n from a population of size N is obtained through simple random sampling if every possible sample of size n has an equally likely chance of occurring. The sample is then called a simple random sample.
20. a list of all the individuals within the population, called a frame.
21. A stratified sample is obtained by separating the population into non overlapping groups called strata and then obtaining a simple random sample from each stratum. The individuals within each stratum should be homogeneous (or similar) in some way.
22. A cluster sample is obtained by selecting all