MySpace |
---|

18 |

18 |

20 |

30 |

35 |

118 |

119 |

123 |

149 |

160 |

167 |

200 |

200 |

200 |

208 |

209 |

300 |

300 |

306 |

400 |

400 |

500 |

546 |

The table is the number of friends reported by MySpace users.

- _____________ Calculate the sample size n.
- _____________ Calculate the sample mean x.
- _____________ Calculate the sample standard deviation sx.
- _____________ Based on the data, what is the point estimate for the population mean μ?
- _____________ Calculate the standard error SE of the mean.
- _____________ Calculate the degrees of freedom n − 1.
- _____________ Calculate t-critical t
_{c}for a confidence level of 95%. - _____________ Calculate the margin of error E for the mean.
- p(__________ ≤ μ ≤ __________) = 0.95 Calculate the 95% confidence interval for the population mean.
- _____________
FaceBook reports that the average number of friends is 130.
Write out the null hypothesis that the population mean μ is 130 friends:

H_{0}: - Write out the alternate hypothesis that the population mean μ is NOT 130 friends:

H_{1}:

Run a hypothesis test at a risk of a type I error alpha α = 0.05 - _____________ Calculate the value of the t-statistic t
- _________________________________ Do we
*reject***or***fail to reject*the null hypothesis? - _____________ Is the MySpace sample mean x statistically significantly different from the FaceBook population mean μ of 130 friends?