Welcome to the NavList Message Boards.


A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Add Images & Files
    Re: Linear regression and other tools
    From: Lars Bergman
    Date: 2018 Oct 11, 11:47 -0700


    A simple example may clarify what I am trying to explain. Consider three pairs of observational data:

    X          Y

    3           15
    4           20
    5           30

    A linear fit of these data gives the expression  Yfit = 7.5 · X - 8.333 which is a straight line that minimize the sum of the squares of the vertical distances between all given Y-values and that line. The formulas to get the two coefficients is shown at the link Tony pointed at.

    The (arithmetic) mean of the X values is Xmean = (3 + 4 + 5) / 3 = 4. If you put this mean value into above expression you get Yfit = 7.5 · 4 - 8.333 = 21.667. This result is actually precisely equal to the mean of the Y values, Ymean = (15 + 20 + 30) / 3 = 21.667.

    So the mean of your X-values and the mean of your Y-values is a point on that best fit line. You don't need to calculate the regression coeficients.


    Browse Files

    Drop Files


    What is NavList?

    Join NavList

    (please, no nicknames or handles)
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.

    Email Settings

    Posting Code:

    Custom Index

    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site