Stat

STAT 32 Take Home Quiz

Perform a hypothesis test and decide whether to reject of fail to reject the null hypothesis.

1. According to a recent study, when shopping online for luxury goods, men spend a mean of $2,401, whereas women spend a mean of $1,527. Suppose that the study was based on a sample of 600 men and 700 females, and the standard deviation of the amount spent was $1,200 for men and $1,000 for women. At the 0.01 level of significance, is there evidence that the mean amount spent is higher for men than for women?

2. Nine experts rated two brands of Colombian coffee in a taste-testing experiment. A rating on a 7-point scale (1 = extremely unpleasing,7=extremely pleasing) is given for each of four characteristics: taste, aroma, richness, and acidity. The data below display the ratings accumulated over all four characteristics. At the 0.05 level of significance, is there evidence of a difference in the mean ratings between the two brands?

| Brand |

Expert | A | B |

C.C | 24 | 26 |

S.E. | 27 | 27 |

E.G. | 19 | 22 |

B.L. | 24 | 27 |

C.M. | 22 | 25 |

C.N. | 26 | 27 |

G.N. | 2 | 26 |

R.M. | 25 | 27 |

P.V. | 22 | 23 |

3. You work for an insurance company and are studying the relationship between types of crashes and the vehicles involved in passenger vehicle occupant deaths. As part of your study, you randomly select 4270 vehicle crashes and organize the resulting data as shown in the contingency table. At α = 0.05, can you conclude that the type of crash depends on the type of vehicle?

| Vehicle |

Type of crash | Car | Pickup | SUV |

Single-vehicle | 1237 | 547 | 479 |

Multiple-vehicle | 1453 | 307 | 247 |

4. A pet association claims that the mean annual costs of routine veterinarian visits for dogs and cats are the same. The results for samples of the two types of pets are shown below. At α=0.10, can you reject the pet association’s claim? Assume the population variances are not equal.

Sample...