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Elem. Stats Ch 1
A Brief Version: Elementary Statistics Ch 1
Question | Answer |
---|---|
Statistics | The science of conducting studies to collect, organize, summarize, analyze, and draw conclusions from data. |
Variable | A characteristic or attribute that can assume different values. |
Descriptive Statistics | Consists of the collection, organization, summarization, and presentation of data. |
Population | Consists of all subjects (human or otherwise) that are being studied. |
Sample | Is a group of subjects from a population. |
Inferential Statistics | Consists of generalizing from samples to population, performing hypothesis tests, determining relationships among variables and making predictions. |
Discrete Variables | Assume values can be counted. |
Continuous Variables | Can assume all values between any two specific values. They are obtained by measuring |
Qualitative Variables | Variables that can be placed into distinct categories, according to some characteristic or attribute. |
Quantitative Variables | Variables that are numerical in nature and can be ordered or ranked. |
Nominal Level of Measurement | Classifies data into mutually exclusive (nonoverlapping), exhausting categories in which no order or ranking can be imposed on the data. |
Ordinal Level of Measurement | Classifies data into categories that can be ranked; however, precise differences between the ranks do not exists. |
Ratio Level of Measurement | Possesses all the characteristics of interval measurement, and there exists a true zero. In addition, true ratios exists when the same variable is measured on two different members of the population. |
Interval Level of Measurement | Ranks data, and precise differences between units of measure do exist; however, there is no meaningful zero. |
Random Samples | Subjects are selected by random numbers or chance methods. |
Systematic Samples | Subjects are selected by using every kth number after the first subject is randomly selected from 1 through k |
Stratified Samples | Subjects are selected by dividing up the population into groups (strata) and subjects within groups are randomly selected. |
Cluster | Subjects are selected by using an intact group that is representative of the population. |
Observational Study | The researcher merely observes what is happening or what has happened in the past and tries to draw conclusions on these observations. |
Experimental Study | The researches manipulated one of the variables and tries to determine how the manipulation influences other variables. |
Independent Variable (Also called Explanatory Variable) | In an experimental study is the one that is being manipulated by the researcher. |
Dependent Variable (Also called Outcome Variable) | The resultant variable of an experimental study. |
Confounding Variable | One that influences the dependent or outcome variable but cannot be separated from the independent variable. |