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# U1L2: Data

### Histograms, box-plots, and measures of central tendency

Term | Definition |
---|---|

frequency | an interval made up of data values in that interval |

frequency table | a table that groups a set of data values into intervals and shows the frequency for each interval |

histogram | a graph that can display data from a frequency table |

cumulative frequency table | a table that shows the number of data values that lie in or below a given interval |

symmetric | describes a graph consisting of two parts that are congruent to each other |

skewed left(negative)/skewed right (positive) | distributions with fewer observations on the left/right |

bell-shaped | when the graph of a data set creates a symmetric bell-shape |

uniform | when the observations in a set of data are equally spread across the range of the distribution |

unimodal/bimodal | distributions with one clear peak/two clear peaks |

gap | areas of a distribution where there are no observations |

outlier | an extreme value that differs greatly from the other observations |

measures of central tendency | measurements that summarize a data set |

mean | the sum of the data values divided by the total number of data values (the average) |

median | the middle value in a data set when the values are arranged in order |

mode | the data item that occurs most times |

measure of dispersion | a measurement that describes how spread out the values in a data set are |

range | the difference between the greatest and least values |

quartiles | values that divide into four equal parts |

interquartile range | the difference between the third and first quartiles |

box-and-whisker plot | a graph that summarizes a set of data by displaying it along a number line |