Business statistics

Question

Based on the data shown below, calculate the regression line (each value to two decimal places)

y =________  x + _______ 

xy
4	31.14
5	28.27
6	29.2
7	25.83
8	23.96
9	23.89
10	21.62
11	21.05
12	17.68
13	17.71
14	14.84
15	16.07
16	11.7

Answer 1

This is fairly difficult to do manually so I'll assume you are allowed to do it using a graphing calculator or using desmos. I'll describe the method that uses the TI-84:

Using a TI-84 Plus CE Graphing Calculator:

1) Push the "stat" button (4 buttons above 8)

2) The "EDIT" and "1:Edit" are highlighted. Press "enter".

3) you will get a tabular screen with L1, L2, L3, etc across the top. If there is any data in the table, use your cursor to scroll to the top of the column to highlight L1 (or whatever has data in it) and press "clear" then "enter" to clear the data. In column L1, type your x-values and in column L2, type you y-values. When done, it will look like this:

L1 | L2 | L3 | L4 | L5 |

4 | 31.14 | | | |

5 | 28.27 | | | |

6 | 29.2 | | | |

7 | 25.83 | | | |

8 | 23.96 | | | |

9 | 23.89 | | | |

10 | 21.62 | | | |

11 | 21.05 | | | |

12 | 17.68 | | | |

13 | 17.71 | | | |

14 | 14.84 | | | |

15 | 16.07 | | | |

16 | 11.7 | | | |

4) Push the "stat" button again and using the cursor controls go right to "CALC" and scroll down to "4:LinReg(ax+b)" and press enter.

5) You will get a screen that says LinReg(ax + b) on top. In the "Xlist:" make sure it says "L1" and in the "Ylist" make sure it says "L2" (you can change these using the "list" command). Scroll down to highlight "Calculate" and press "enter" you will get a screen that says:

y = ax + b

a = -1.51010989

b = 36.86725275

These are the values you are looking for.

If you need help with the desmos version, leave me a comment.