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Chapter 1 - Nature of Probability and Statistics
Chapter one of Elementary statistics
37
Mathematics
Undergraduate 1
08/27/2013

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Term
Statistics
Definition
The science of conducting studies to collect, organize, summarize, analyze, and draw conclusions from data.
Term
Variable
Definition
A characteristic or attribute that can assume different values (the final exam grade for all students taking a class).
Term
Data
Definition
The values (measurements or observations) that the variables can assume.
Term
Data Set
Definition
A collection of data values that forms a data set (80,75,98).
Term
Data Value / Datum
Definition
Each value in a data set (80).
Term
Random Variables
Definition
Variables whose values are determined by chance.
Term
Statistics Types
Definition
Descriptive Statistics and Inferential Statistics
Term
Descriptive Statistics
Definition
Statistics consisting of the collection, organization, summarization, and presentation of data. (census)
Term
Inferential Statistics
Definition
Statistics which consist of generalizing from samples to populations, performing estimations and hypothesis tests, determining relationships among variables, and making predictions.
Term
Probability
Definition
the chance of an event occurring
Term
Population
Definition
A group consisting of all subjects (human or otherwise) which are being studies
Term
Sample
Definition
A group of subjects selected from a population.
Term
Hypothesis Testing
Definition
A decision-making process used for evaluating claims about a population based on information obtained from samples.
Term
Qualitative and Quantitative Variables
Definition
Types of data uses in statistical studies
Term
Qualitative Variables
Definition
Variables that can be placed into categories based on some distinct characteristic or attribute. (gender, religion, etc)
Term
Quantitative Variables
Definition
Variables which are numerical and can be ordered or ranked. (age, IQ, weight, etc)
Term
Discrete Variables and Continuous Variables
Definition
Classifications of quantitative variables.
Term
Discrete Variables
Definition
Variables that can be assigned numbers such as 0, 1, 2, 3 and are said to be countable.
Term
Continuous Variables
Definition
Variables which can assume an infinite number of values between any two specific values. They are obtained by measuring, and they often include fractions and decimals. (Rounded but have boundaries - 73 could be any value from 72.5-73.5 not including 7.35)
Term
Measurement Scales
Definition
How variables are counted, categorized, or measured (nominal, ordinal, interval, ratio).
Term
Nominal
Definition
Level of measurement which classifies data into mutually exclusive (nonoverlapping) categories in which no order or ranking can be imposed on the data. (political party, religion, etc)
Term
Ordinal
Definition
The level of measurement which classifies data into categories that can be ranked; however, precise differences between the ranks do not exist. (letter grade, order of floats in parade, etc)
Term
Interval
Definition
Level of measurement which ranks data, and precise differences between units of measure do exist; however, there is no meaningful zero. (always exists, such as temperature, IQ, etc)
Term
Ratio
Definition
Level of measurement which possesses all the characteristics of interval measurement, and there exists a true zero. In addition, true ratios exist when the same variable is measured on two different members of the population. (amount of weight that can be lifted, amount of money in pocket, etc)
Term
Random, Systematic, Stratified, Cluster
Definition
The four basic methods of sampling used in statistics
Term
Random Sampling
Definition
Samples are selected by using chance methods or random numbers
Term
Systematic Sampling
Definition
Samples are obtained by numbering the subjects in the population and selecting the kth subject.
Term
Stratified Sampling
Definition
Samples are selected by dividing the population into groups (called strata) according to some characteristic that is important to the study, then sampling from each group.
Term
Cluster Sampling
Definition
Samples are selected by dividing the population into groups called clusters by some means such as geographic area or schools in a large school district, etc. Then the researcher randomly selects some of these clusters and uses all members of the selected clusters as the subjects of the samples
Term
Convenience Sampling
Definition
Sampling done by using subjects that are convenient (all people entering a mall)
Term
Types of statistical studies
Definition
Observational study and Experimental study
Term
Observational Study
Definition
A study in which the researcher merely observes what is happening or what has happened in the past and tries to draw conclusions based on these observations.
Term
Experimental Study
Definition
A study in which the researcher manipulates one of the variables and tries to determine how that manipulation influences the other variables.
Term
Independent Variable
Definition
The variable in an experimental study which is being manipulated by the researcher - also called the explanatory variable.
Term
Dependent Variable
Definition
The variable in an experimental study which is measured to see if it has changed significantly due to the manipulation of the independent variable. Also called the outcome variable.
Term
Confounding Variable
Definition
A variable in an experimental study which influences the dependent or outcome variable but was not separated form the independent variable. (better diet in exercise experiment)
Term
Hawthorne Effect
Definition
Effect discovered during an experiment which showed people change their actions or behaviors when they know they are being observed.
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