Flashcards
statistics
Flashcards do conjunto (18)
- 1StatisticsThe science of the collection, analysis and presentation of data.
- 2DataInformation collected about people or things.
The investigative process: - 3VariableThe characteristic of interest for each person or thing in a population.
- 4Qualitative variablescan take on values that are names or labels.
- 5Quantitative variablescan take on numeric values. There are two types of quantitative variables: discrete and continuous.
- 6Discrete variablescan take on a countable and/or finite number of values (e.g. counts)
- 7Continuous variablescan take on an infinite number of possible values in some interval (e.g. measurements)
- 8CensusA census is a study that obtains data from every member of a population, which is a complete collection of all people or things under study. In most studies, a census is not practical, because of the cost and time required.
- 9Sample SurveysA sample survey is a study that obtains data from a subset of a population, called a sample, and generalizes results to the larger population.
- 10Parameter: a number that describes a population.
- 11Statistica number that describes a sample.
- 12A well-designed sample survey can provide very precise estimates of population parameters. As long as members of a sample are randomly selected from a larger population, it is appropriate to generalize the results to the larger population.A well-designed sample survey can provide very precise estimates of population parameters. As long as members of a sample are randomly selected from a larger population, it is appropriate to generalize the results to the larger population.
- 13Important notes about sampling:Ideally, a sample should be representative of the population. A sample that is not representative of the population is biased.
The random error obtained by using part of the population to represent the whole population is called sampling error.
The non-random error caused by improper data collection recording or sampling techniques, is called non-sampling error.
With random sampling, each member of a population has an equal chance of being selected. - 14Systematic sampling: Select some starting point and then select every kth element in the population.
- 15Stratified samplingSubdivide the population into at least two different subgroups (or strata) that share the same characteristics, then draw a simple random sample from each subgroup.
- 16Cluster samplingDivide the population area into sections (or clusters), then randomly select some of those clusters; then choose all of the members from those selected clusters.
- 17Convenience samplingUse results that are easy to obtain.
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- FlashCards sobre statistics, criado por Max Goodman em 04-02-2019.
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- Max Goodman
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