# Chapter 5: Measures of Variability

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

What is the Measure of variability? | It is a number that describes diversity or variability in the distribution. Basically it shows us how much variation and diversity there is within the answers we received. |

What are the five measures of variability? | The index of qualitative variation, The range, The interquartile rage, The standard deviation and The variance |

What is the Index of Qualitative Variation (IQV)? | It is a measure of variability for nominal variables like race or ethnicity. |

What is the range of the Index of Qualitative Variation (IQV)? | It is a number that can range from 0.00 to 1.00. |

What is the value of the IQV if there is no variation? | 0.00 |

What is the value of the IQV if there is maximum variation? | 1.00 |

What is the equation for calculating the IQV? | IQV = Total Observed Differences / Total Possible Differences OR IQV = K(n2 – ?f2) / n2 (K-1) |

What is the IQV based on? | it is based on a ratio of the total number of differences in the distribution to the maximum number of possible differences within the same distribution. |

What is the range? | it is the difference between the highest score and lowest score in the distribution. |

Which level of variables does the range measure? | The Ordinal level |

What is the Inter-Quartile Range (IQR)? | The width of the middle 50 percent of the distribution. It is defined as the difference between the lower and upper quartiles (Q1 and Q3.) |

What is the equation for the IQR? | IQR= Q3-Q1 |

How is the Box Plot used? | It is a graphic device that visually presents the following elements: the range, the inter-quartile range, the median, the quartiles, the minimum (lowest value,) and the maximum (highest value.) |

How do you calculate the first quartile (q1)? | Q1= n (.25) |

How do you calculate the third quartile (q3)? | Q3= n (.75) |

Where do you start when you are identifying the values associated with the first and third quartile? | The bottom, or smallest value (assuming the values are already ordered from highest to lowest) |

What is the variance? | It is the average of the squared deviations for the mean of the distribution. |

What is the standard deviation? | It is the square root of the variance |

Which measures of variability measure Interval-Ratio variables? | Variance and Standard Deviation. |

What is the equation for finding the variation? | sy2= E (Y-Y)^2 / N-1 |