# 1)Annual high temperatures in

1)Annual high temperatures in a certain location have beentracked for several years. Let X represent the year and Y the hightemperature. Based on the data shown below, calculate theregression line (each value to two decimal places).y = _____________ x + ________________

x | y |
---|---|

3 | 10.42 |

4 | 10.96 |

5 | 13.8 |

6 | 17.14 |

7 | 16.98 |

8 | 21.22 |

9 | 23.96 |

10 | 23.9 |

11 | 27.14 |

12 | 30.28 |

13 | 30.22 |

14 | 34.06 |

15 | 37.1 |

16 | 36.74 |

17 | 41.08 |

18 | 41.62 |

2) Annual high temperatures in a certain location have beentracked for several years. Let X represent the year and Y the hightemperature. Based on the data shown below, calculate thecorrelation coefficient (to three decimal places) between X and Y.Use your calculator!

x | y |
---|---|

4 | 22.68 |

5 | 21.8 |

6 | 23.42 |

7 | 24.24 |

8 | 25.86 |

9 | 28.68 |

10 | 32.9 |

11 | 31.92 |

12 | 36.24 |

13 | 36.26 |

14 | 36.18 |

15 | 41.4 |

16 | 43.02 |

r=

3)Recently a community college offered a 2-credit course to helpstudents with math anxiety. At the beginning of the course, eachstudent took a 30-question survey (called MARS-S); the higher thescore, the more anxiety experienced by the student. The ninestudents remaining in the class took the same survey at the end ofthe course. The before and after scores for each of the ninestudents who completed the course are shown below.

student | before | after |

1 | 72 | 69 |

2 | 66 | 52 |

3 | 83 | 71 |

4 | 97 | 85 |

5 | 95 | 61 |

6 | 78 | 45 |

7 | 95 | 56 |

8 | 52 | 43 |

9 | 93 | 62 |

Compute the correlation between before and after scores for thesestudents. (Assume the correlation conditions have been satisfiedand round your answer to the nearest 0.001.)

Answer:

**Answer 1:**

The equation of the regression line is:

y = **3.21** +**2.17***x

**Answer 2:**

The correlation coefficient is:

r = **0.980**

**Answer 3:**

The correlation coefficient is:

r = **0.588**