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anonymous

  • one year ago

What is the equation of this line of best fit in slope-intercept form?

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  1. anonymous
    • one year ago
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    Dan drew the line of best fit on the scatter plot shown below:

  2. Michele_Laino
    • one year ago
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    here we have to apply the least square method, in order to get the right equation for constants A and B, such that: y=Ax+B

  3. Michele_Laino
    • one year ago
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    equations*

  4. anonymous
    • one year ago
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    Since you already have the line of best fit you first need to understand the concept of slope-intercept form which is: y = mx + b I'd first calculate the y-intercept then slope.

  5. anonymous
    • one year ago
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    so then Its either y = 3x + 5/6 or y = 3x + 6/5

  6. anonymous
    • one year ago
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    You're mixing the y-intercept and slope up… the y-intercept is the point of the line where x = 0. That would make (0, 3) the y-intercept.

  7. anonymous
    • one year ago
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    As for the slope, try again.. you understand the basic concept.

  8. anonymous
    • one year ago
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    The y-intercept is where the point and line meets?

  9. Michele_Laino
    • one year ago
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    here are the formulas for the coefficients A, and B: \[\Large \left\{ \begin{gathered} A = \frac{{N\sum {{x_i}{y_i} - \left( {\sum {{x_i}} } \right)\left( {\sum {{y_i}} } \right)} }}{{N\sum {x_i^2 - {{\left( {\sum {{x_i}} } \right)}^2}} }} \hfill \\ \hfill \\ \hfill \\ B = \frac{{\left( {\sum {x_i^2} } \right)\left( {\sum {{y_i}} } \right) - \left( {\sum {{x_i}} } \right)\sum {{x_i}{y_i}} }}{{N\sum {x_i^2 - {{\left( {\sum {{x_i}} } \right)}^2}} }} \hfill \\ \end{gathered} \right.\]

  10. anonymous
    • one year ago
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    The y-intercept is where the line crosses the y-axis.

  11. Michele_Laino
    • one year ago
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    where N is the number of experimental points

  12. anonymous
    • one year ago
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    experimental points? what does the E stands for?

  13. Michele_Laino
    • one year ago
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    where is the E ?

  14. Michele_Laino
    • one year ago
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    with experimental points, i mean the number of points, namely: N=11

  15. anonymous
    • one year ago
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    The big numberal sign you see repeating

  16. anonymous
    • one year ago
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    '∑' this sign ?

  17. anonymous
    • one year ago
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    Oooh it stands for equation

  18. Michele_Laino
    • one year ago
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    it is the capital \sigma

  19. Michele_Laino
    • one year ago
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    \[\Large \Sigma \] stands for summation

  20. anonymous
    • one year ago
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    Im not getting how to find the slope intercept..?

  21. Michele_Laino
    • one year ago
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    for example, we have: \[\Large \sum\limits_{i = 1}^5 {{x_i}} = {x_1} + {x_2} + {x_3} + {x_4} + {x_5}\]

  22. anonymous
    • one year ago
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    O_O what does all those signs and numbers suppose to mean again?

  23. anonymous
    • one year ago
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    Im not sure anybody told me yet :-:

  24. Michele_Laino
    • one year ago
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    nevertheless I think that we have to write the equation of the line represented in your drawing. In order to that we note that your line passes at point (5,9) and at point (10,15) so we have to write the equation of a line which passes at those points

  25. anonymous
    • one year ago
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    oh ok .. O_o

  26. anonymous
    • one year ago
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    In order to calculate slope, note that it is rise/run or: y2 - y1/x2 - x1 (Using two points to plug in)

  27. anonymous
    • one year ago
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    I remember hearing about rise over run

  28. anonymous
    • one year ago
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    but what does the numbers do ?

  29. anonymous
    • one year ago
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    Awesome! The numbers next to the x and y are sub numbers… they don't really mean anything

  30. anonymous
    • one year ago
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    I mainly used to refer to them as numbers that would help me keep organized

  31. anonymous
    • one year ago
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    Oh so they are just for show?

  32. anonymous
    • one year ago
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    Technically, no, but you can look at it that way :)

  33. anonymous
    • one year ago
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    Oh ok

  34. anonymous
    • one year ago
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    You pronounce "y2" as "y sub 2"

  35. anonymous
    • one year ago
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    if i had a equation like this : y = 3x + 6/5 why is there a fraction in their and what do i do about it

  36. anonymous
    • one year ago
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    Well, "6/5" represents slope: meaning that you would rise 6 units, and run (towards the right since it is positive) 5 units.

  37. anonymous
    • one year ago
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    Oh ok I think Im good thanks

  38. anonymous
    • one year ago
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    Okay, cool! So, usually I start at the y-intercept before I rise or run if I have a graph.. there are many ways to calculate slope, but since you have a graph, it's easier to have a visual representation that way.

  39. anonymous
    • one year ago
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    |dw:1436729744129:dw|

  40. anonymous
    • one year ago
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    So, we can choose ANY two points that are on the line.

  41. anonymous
    • one year ago
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    Let's take: (1, 4) (5, 9)

  42. anonymous
    • one year ago
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    We can name both of these pairs as: (x1, y1) (x2, y2) Make sense?

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