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# Stack #362116

### WGU TBA4 Statistics

Question | Answer |
---|---|

discrete | result when the number of possible values is either a finite number or a countable number |

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

parameter | a numerical measurement describing some characteristic of a population |

statistic | a numerical measurement describing some characteristic of a sample |

nominal | categories only; data cannot be arranged in an ordering scheme |

ordinal | categories are ordered, but differences cannot be found or are meaningless |

interval | differences are meaningful, but there is no natural zero starting point and ratios are meaningless |

ratio | there is a natural zero starting point and ratios are meaningful |

voluntary response sample | one in which the respondents themselves decide whether to be included |

observational study | observe and measure specific characteristics, but don't attempt to modify the subjects being studied |

experiment | apply some treatment and then proceed to observe its effects on the subjects |

cross-sectional study | data are observed, measured, and collected at one point in time |

retrospective study | data are collected from the past by going back in time |

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

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

simple random sample | n subjects is selected in such a way that every possible sample of the same size n has the same chance of being chosen |

probability sample | selecting members from a population in such a way that each member has a known chance of being selected |

systematic sampling | select some starting point and then select every kth element in the population |

convenience sampling | simply use the results that are very easy to get |

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

cluster sampling | first divide the population area into sections, then randomly select some of those clusters, and then chose all the members from those selected clusters |

simulation | a process that behaves the same way as the procedure, so that similar results are produced |

conditional probability | a probability obtained with the additional information that some other event has already occurred |

event | any collection of results or outcomes of a procedure |

simple event | an outcome or event that cannot be further broken down into simpler components |

sample space | consists of all possible simple events |

complement | consists of all outcomes in which event does not occur |

random variable | a variable that has a single numerical value, determined by chance, for each outcome of a procedure |

probability distribution | a description that gives the probability for each value of the random variable, often expressed in the format of a graph, table, or formula |

discrete random variable | either a finite naumber of values or a countable number of values, where "countable" refers to the fact that there might be infinitely many values, but they can be associated with a counting process |

continuous random variable | infinitely many values, and those values can be associated with measurements on a continuous scale without gaps or interruptions |