### MS 150 Statistics quiz 05 • Name:

- __________ What is the probability that "our unguessable password" is p455w0rd?
- __________ What level of measurement is the password data?
- __________ If this was really the basis of a large scale study, what is the mode?

A convenience sample of 43 students in MS 150 Statistic fall 2007 yielded the following results:

Psychoactive | Frequencies |

Substance | Never | About once a month | About once a week |
A few times a week | Every day |

Betelnut without tobacco | 29 | 7 | 3 | 2 | 3 |

Betelnut with tobacco | 22 | 0 | 1 | 3 | 17 |

- __________ Consider just the first data row, the data on those who chew without tobacco. What is the probability that a student does not chew betelnut?
- __________ Consider just the first data row, the data on those who chew without tobacco. For those
**who do chew**, what is the mode?
- __________ Consider just the second data row, the data on those who chew with tobacco. For those
**who do chew**, what is the mode?
- Considering the above two mode results, what impact does tobacco appear to have on betelnut chewing habits?

Bin upper limit for number of elements (x) | Frequency f | Rel freq, p(x) | x*p(x) |

5 | 5 | 0.04 | 0.18 |

10 | 12 | 0.09 | 0.88 |

15 | 30 | 0.22 | 3.31 |

20 | 50 | 0.37 | 7.35 |

25 | 25 | 0.18 | 4.60 |

30 | 9 | 0.07 | 1.99 |

35 | 5 | 0.04 | 1.29 |

Sums: | 136 | 1.00 | **19.60** |

The data in the table is adapted from a study done by Eelmine Järgmine on the number of elements found in a web page. A larger study by Google confirms this data. Although the data is technically not continuous data, use the table to report the mean number of different html elements found on a typical Internet web page.

- __________ What is the mean number of elements found on a typical web page?