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STA CH 1
CH 1
Question | Answer |
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Statistics | Is the science of data |
Two branches of statistics? | Descriptive statistics,Inferential statistics |
Descriptive Statistics | Consists of the collection, organization, summarization, and presentation of data |
Inferential Statistics | Consists of generalizing from samples to populations by.. Performing estimations and hypothesis tests,Determining relationships among variables,Making predictions, Uses probability( the chance of an event occurring) |
Population | Consists of all subjects (human or otherwise) that are being studied. |
Sample | Is a group of subjects selected from a population. |
Variable | Is a characteristic or attribute that can assume different values. |
Data | are the values (measurements or observations) that the variables can assume. |
Random variable | variables whose values are determined by chance. |
Types of Data | Variables can be classified as qualitative or quantitative |
Qualitative | variables that can be placed into distinct categories, according to some characteristic or attribute |
Quantitative | variables that are numerical and can be ordered or ranked |
Qualitative Variables | Categorical, Can be further classified into two groups, nominal and ordinal |
Nominal Data | data can be classified into mutually exclusive (non-overlapping) categories in which no order or ranking can be imposed. |
Ordinal data | can be classified into categories that can be ranked or ordered |
Quantitative Variables | Numerical,Can be further classified into two groups, discrete and continuous. |
Discrete variables | can be assigned values such as 0, 1, 2, 3 and are said to be countable. Obtained by counting |
Continuous variables | can assume an infinite number of values in an interval between two specific values. Obtained by measuring |
inferential statistics goal | learn about a population by using a sample |
unbiased samples | Each subject in the population has an equally likely chance of being selected. |
Observational study | the researcher observes what is happening (or what has happened in the past) and tries to draw conclusions based on these observations. |
Experimental study | the researcher manipulates one of the variables and tries to determine how the manipulation influences other variables. |
independent variable | one that is being manipulated by the researcher |
dependent variable | the outcome |