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Calculators Trend Lines on HP50G

  1. Jul 3, 2010 #1

    I'm taking 3rd semester chemistry and we often have to take a series of for instance:
    Absorbance vs. concentrations data.

    Usually a series 5 experiments with the goal to have a spread sheet type answer. I use Excel or what ever I have handy just to find the y=mx + b value for "m".

    I want to use my HP50G to accomplish this while in class.

    I looked in the HP50G manual and there does appear to be a way to create trend lines but is not working for me. The examples are a bit more involved in the answers.

    I have a feeling I'm doing something wrong in the chose of which menu to use.... I know my inputs are correct and formatted correctly so either this isn't possible or as I said I'm starting out on the wrong foot.

    here's what I've been doing according to the manual:

    Stats > Fit data > Linear Fit
    I enter the data in A column=x axis, B column=Y axis

    Answers not in the format I need.
    None of the other choses seem to get me there either..

    is there a simple way to do what I'm attempting so I have this with me always?


  2. jcsd
  3. Jul 3, 2010 #2
    Actually All I'm after is a way to use a linear regression on a series of data points Y vs. X.

    Any advise welcome.

  4. Jul 26, 2010 #3

    You should see a screen that shows [tex]\sigma[/tex]DAT, X-Col, Y-Col, and Model. Choose Linear Fit for the Model, and X-Col and Y-Col as 1 and 2, respectively. When entering data, make sure that the X values are listed in the first column, and the Y values are listed in the second column (as per your settings). Here's a sample data set:

    (1,5) (2,10) (3,15) (4,20)

    On the calculator, this should appear in the matrix editor as as:

    1 5
    2 10
    3 15
    4 20

    Upon pressing OK, you should see:

    [itex]0.+5. \cdot X[/itex]
    Correlation: 1.
    Covariance: 8.3333333333

    This means your "m" is 5. and your "b" is 0.
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