Shortly after being put into service, some buses manufactured by a certain company have developed cracks on the underside of the main frame. Suppose a particular city has 25 of these buses, and cracks have actually appeared in 8 of them.(adsbygoogle = window.adsbygoogle || []).push({});

(i) How many ways are there to select a sample of 5 buses from the 25 for a thorough inspection?

(ii) How many of these samples of 5 buses contain exactly 4 with visible cracks?

(iii) If a sample of 5 buses is chosen at random, what is the probability that exactly 4 of the 5 will have visible cracks (to 3 dp)?

(iv) If buses are selected as in part (iii), what is the probability that at least 4 of those selected will have visible cracks (to 3 dp)?

answers:

(i) 25 buses, 5 choices so: 25C5 = 53130

(ii) 5 buses, 8 broken so: (8C4)(17C1) = 1190

(iii) 53130/1190

(iv)

at least 4, so:

{(8C4)(17C1) + (8C5)(17C0)} / 25C5

can you check my answers? thanks.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# General probability question

Loading...

Similar Threads for General probability question |
---|

I Non-countable uniform spaces probability |

I Probability of equally likely events |

A How to calculate the probability of error in an AWGN channel? |

A Sum of independent random variables and Normalization |

A Sample Test | Component Lifetime |

**Physics Forums | Science Articles, Homework Help, Discussion**