Intro Into Statistics

Exercise 5-57 Assume there are 23 homes in the Quail Creek area and 9 of them have a security system. Four homes are selected at random: |

(a) | What is the probability all four of the selected homes have a security system? (Round your answer to 4 decimal places.) |

Probability | |

(b) | What is the probability none of the four selected homes have a security system? (Round your answer to 4 decimal places.) |

Probability | |

(c) | What is the probability at least one of the selected homes has a security system? (Round your answer to 4 decimal places.) |

Probability | |

(d) | Are the events dependent or independent? | | | | |

rev: 02-04-2011 Explanation:
(a)
0.0142, found by (9/23)(8/22)(7/21)(6/20)

(b)
0.1130, found by (14/23)(13/22)(12/21)(11/20)

(c)
0.8870, found by 1 − 0.1130

Exercise 5-37 An overnight express company must include thirteen cities on its route. How many different routes are possible, assuming that it matters in which order the cities are included in the routing? | Number of different routes | |

Explanation:
6,227,020,800, found by 13!
Exercise 5-26 All Seasons Plumbing has two service trucks that frequently need repair. If the probability the first truck is available is .73, the probability the second truck is available is .56, and the probability that both trucks are available is .46: |

What is the probability neither truck is available? (Round your answer to 2 decimal places.) | Probability | |

Explanation:

0.17, found by (1 − 0.83)

Exercise 5-27 Refer to the following table. | Second Event | First Event | | | A1 | A2 | A3 | Total | B1 | 3 | 4 | 6 | 13 | B2 | 3 | 5 | 5 | 13 | Total | 6 | 9 | 11 | 26 |

(a) | Determine P(A3). | P(A3) = | |

(b) | Determine P(B1|A1). | P(B1|A1) = | |

(c) | Determine P(B1 and A2). |