Month | Water |
---|---|

January | 830 |

February | 5560 |

March | 11390 |

April | 8330 |

May | 5280 |

June | 10010 |

July | 5000 |

August | 10560 |

September | 10260 |

October | 9790 |

The data is the gallons of water used in a home per month in 2013.

- n = __________ Calculate the sample size n.
- x = __________ Calculate the sample mean x.
- sx = __________ Calculate the sample standard deviation sx.
- SE = __________ Calculate the standard error SE.
- t
_{c}= ____________________ Given a confidence level c = 0.95, calculate t_{critical} `E`= _________ Calculate the margin of error E for the sample mean x.- Write out the 95% confidence interval for the possible population mean μ

p(_____________ < μ < ___________) = 0.95 - _______________ In 2012 the home was averaging 12800 gallons per month at an average cost of $30.34 per month. The family in the home committed to using less water per month in 2013. Is 12800 gallons a possible population mean for the sample data?
- _______________ Did the home use statistically significantly less water per month in 2013 at a confidence level of 95%?

Given a null hypothesis of H_{0}: μ = 12800

and the alternative hypothesis of H_{1}: μ ≠ 12800

Run a hypothesis test at a risk of a type I error alpha α = 0.05 - t = ____________________ Calculate the t-statistic t
- p-value = ____________________ Use =tdist(abs(t),n−1,2) to calculate the p-value.
- ____________________ Calculate the largest possible confidence interval which does not include 12800 by calculating 1 − p-value.
- ____________________ Is the sample mean x statistically significantly different from the population mean μ of 12800?
- _____________________ At an alpha α of 5%, would you
*fail to reject***|or|***reject*the null hypothesis? - _______________ Is the home using less water in 2013 at an alpha of 5%?