SOLUTION: Thank you for helping me! I need to make a scatter plot of the data and find the equation of the best fitting line, and approximate the value of y for x = 3. x= -1, 0, 1 , 2, 4

Algebra ->  Coordinate-system -> SOLUTION: Thank you for helping me! I need to make a scatter plot of the data and find the equation of the best fitting line, and approximate the value of y for x = 3. x= -1, 0, 1 , 2, 4       Log On


   



Question 1190695: Thank you for helping me!
I need to make a scatter plot of the data and find the equation of the best fitting line, and approximate the value of y for x = 3.
x= -1, 0, 1 , 2, 4
y = 3,3,1,0,-3
I plotted the graph but I don't know how to do the rest, thank you very much.

Found 2 solutions by ikleyn, math_tutor2020:
Answer by ikleyn(52782) About Me  (Show Source):
You can put this solution on YOUR website!
.

From this source

https://chartio.com/learn/charts/what-is-a-scatter-plot/#:~:text=A%20scatter%20plot%20(aka%20scatter,to%20observe%20relationships%20between%20variables.

which is called  " A Complete Guide to Scatter Plots "


                        D E F I N I T I O N


    A scatter plot (aka scatter chart, scatter graph) uses dots to represent values for two different numeric variables. 
    The position of each dot on the horizontal and vertical axis indicates values for an individual data point. 
    Scatter plots are used to observe relationships between variables.


See also

https://en.wikipedia.org/wiki/Scatter_plot


So,  as I understand this definition,  a scatter plot is simply a set of dots,  like a  " cloud "  of dots,  literally.


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You do not give details of your assignment, so it is not totally clear what is its goal,
and a prediction can be made in many different ways.

You may ask GOOGLE about "the best fitted curve online".

It will give you several web-sites, where you can find numerous online calculators for this purpose,
even with graphical support,

for example, these websites

https://mycurvefit.com/

https://planetcalc.com/8735/


You may play with them and select, which one is best fitted to you.


Probably, you can find similar tools in your pocket calculator.




Answer by math_tutor2020(3817) About Me  (Show Source):
You can put this solution on YOUR website!

Here's the original table
xy
-13
03
11
20
4-3


Form the column of xy values by multiplying each x and y number for each separate row.
Example: Row 1 has x*y = -1*3 = -3
xyxy
-13-3
030
111
200
4-3-12


Now compute the column of x^2 values
xyxyx^2
-13-31
0300
1111
2004
4-3-1216

We'll get the sum of each column
A = sum of the x values = -1+0+1+2+4 = 6
B = sum of the y values = 3+3+1+0+(-3) = 4
C = sum of the xy values = -3+0+1+0+(-12) = -14
D = sum of the x^2 values = 1+0+1+4+16 = 22

Then we can compute the slope m based on those values computed
m+=+%28C%2An+-+A%2AB%29%2F%28D%2An+-+A%5E2%29
where n is the number of points
In this case, n = 5

So the slope is,
m+=+%28C%2An+-+A%2AB%29%2F%28D%2An+-+A%5E2%29

m+=+%28-14%2A5+-+6%2A4%29%2F%2822%2A5+-+6%5E2%29

m+=+-1.27027 approximately

And the y intercept b is
b+=+%28B-m%2AA%29%2Fn

b+=+%284-%28-1.27027%29%2A6%29%2F5

b+=+2.324324 also approximate.

The regression line is approximately y+=+-1.27027x+%2B+2.324324
For larger data sets, I recommend using a calculator to make quick work of finding the regression line. Also, they are handy to check your answer.

I'll let you plug in x = 3 to find the corresponding y estimate value.