Math 2301
Terms
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- Statistics
- the science of conduction studies to collect, organize, summarize, analyze, and draw conclusions from data.
- Variable
- A characterisitc or attibute that can assume different values.
- Data
- the values (*measuremetns or observations) that the variables can assume.
- Random variables
- Variables whose vvalues are determined by chance.
- Data set
- A collection of data values.
- Data value or datum
- Each value in the data set.
- Descriptive statistics
- Consists of the collection, organization, summarization, and presentation of data.
- Inferential statistics
- Consista of generalizing from sampes to opulations, performing estimations and hypothesis tests, determiming relationships among varible, and making predictions.
- Probablity
- The chance of an event occuring.
- Population
- Consists of all subjects (human or otherwise) that are being studied.
- Sample
- a group of subjects selected from a population.
- Hypthesis Testing
- A decision-making process for evaluating claims about a population, basedon information obtained from samples.
- Qualitatiev Variables
- Variables that can be placed into distinct categories, according to some characteristic or attibute.
- Quantitative Variables
- Are numerical and can be ordered or ranked.
- Discrete variables
- Are assumed valeus that can be counted.
- Continuous variables
- Can assume an infinite number of values between any two specific values. They are obtained by measuring. They often include fractions and decimals.
- Measurement cales
- How vaiables are categorized, counted, or measured.
- Nominal level of measurement
- Calassifies data into mutually exclusive (nonoverlappoiing), exhausting categories in which on order or ranking can be imposed on the data.
- Ordinal level of measurement
- Classifies data into categories that ccan be ranked; however, precise differences between the ranks do not exist.
- Interval level of measurement
- Ranks data, and precise differences between units of measure do exist; however, there is no meaningful zero.
- Ratio level of measurement
- Possesses all the characteristic os interval measurement, and there exist a true zero. In addition, true ratios exist when the same variable is measured on two different members of the population.
- Random sampling
- Selected by using chance methods or random numbers.
- Systematic Sampling
- Obtained by numbering each subject of the population and then selecting ever kth subject.
- Stratified Sampling
- Obtained by dividing the population into groups (called strat) according to some characteristic that is important to teh study, then sampling from each group. Samples within the strata shoudl be randomly selected.
- Cluster Sampling
- The population is divided into groups called clusters by some means such as geographic area or schools in a large school distric, ect. Then the researcher randomly selects some of these clusters and uses all members of the selecte cluster as the subjects of the samples.
- Convenience Sample
- Researchers use subjects that are convenient.
- Observational Study
- The researcher mrely 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 manipuation influences other variables.
- Quasi-experimenta study
- Like experiemental, but uses intact groups.
- Independent variable
- In an experimental study is the one that is being manipuated by the researcher. aka: explanatory variable.
- Dependent variable
- The resultant variable from an independent variable. aka: Outcome variable.
- Treatment group
- The group that received the special instruction
- Control group
- The group that did not recieve special instruction
- Hawthorne Effect
- Researchers foudn that subjects who knew they were participating in an experiemtn actually changed thier behavior in ways the affeced the results of the study.
- Confounding variables
- On that influeences the dependent or outcome variable but cannot be separated from the independent variable.