convenience sampling | | data that results when the number of possible values is either a finite number or a "countable number" |

observational study | | the collection of data from every member of the population |

sample | | observations (such as measurements, genders, survey responses) that have been collected |

experiment | | we first divide the population area into sections, then randomly select some of those clusters, and then choose all the members from those selected clusters |

placebo effect | | study in which data are collected from the past by going back in time |

cross-sectional | | a numerical measurement describing some characteristic of a population |

systematic sampling | | consist of numbers representing counts or measurements |

population | | we subdivide the population into at least two different subgroups that share the same characteristics, then we draw a sample from each subgroup |

parameter | | the difference between a sample result and the true population result |

prospective | | observes and measures specific characteristics, but doesn't attempt to modify the subjects being studied |

sampling error | | study in which data are observed, measured, and collected at one point in time |

random sample | | occurs when an untreated subject incorrectly believes that he or she is receiving a real treatment and reports an improvement in symptoms |

qualitative data | | the complete collection of all elements to be studied |

blinding | | study in which data are collected in the future from groups sharing common factors |

nonsampling error | | data that results from infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions, or jumps |

statistic | | procedure used in experiments whereby the subject doesn't know whether he or she is a receiving a treatment or a placebo |

stratified sampling | | a numerical measurement describing some characteristic of a sample |

data | | a subcollection of members selected from a population |

cluster sampling | | can be separated into different categories that are distinguished by some nonnumerical characteristic |

retrospective | | occurs in an experiment when the experimenter is not able to distinguish between the effects of different factors |

discrete | | we simply use results that are very easy to get |

census | | we select some starting point and then select every nth element in the population |

quantitative data | | members from the population are selected in such a way that each individual member has an equal chance of being selected |

continuous | | applies some treatment and then proceeds to observe its effects on the subjects |

confounding | | occurs when the sample data are incorrectly collected, recorded, or analyzed |