Statistical Literacy and Critical Thinking

In Exercises 21–28, use the same list of 24 sorted Old Faithful eruption duration times given for Exercises 17–20. Find the indicated

percentile or quartile.

Q 1

Answer:

Step 1 of 1

The first quartile is the point at which one fourth of the data lies below it, One fourth is equal to 25%, and so the first quartile is the 25th percentile. It is denoted by

1 |
110 |

2 |
120 |

3 |
178 |

4 |
213 |

5 |
234 |

6 |
234 |

7 |
235 |

8 |
237 |

9 |
240 |

10 |
243 |

11 |
245 |

12 |
245 |

13 |
250 |

14 |
250 |

15 |
251 |

16 |
252 |

17 |
254 |

18 |
255 |

19 |
255 |

20 |
259 |

21 |
260 |

22 |
266 |

23 |
269 |

24 |
273 |

=

= 6.25

Here, 6.25th observation lies in between 6th and 7th value in the ordered group.

Now, 6th value = 234

7th value = 235

Thus, = 6th value + 0.25(7th value - 6th value)

= 234 + 0.25(235 - 234)

= 234 + 0.25

= 234.25 sec.