1: write the equation of the line of best fit using the slope-intercept formula y=mx+b. show all your work, including the points used to determine the slope and how the equation was determined.

2: test the residuals of two other points to determine how well the line of best fit models the data.

3: using the line of best fit that you found in part three, question 2, approximate how tall is a person whose arm span is 66 inches?

4: according to your line of best fit, what is the arm span of a 74-inch-tall person?

Linear correlation equation

Step-by-step explanation:

1) The procedure is very easy. I don't currently have the graph data (Points x, y) but I use Photoshop to draw a rule between the points and approximate values that I show in the table below.

These values refer to each of the blue dots in your graph.

X      Y

45      39.4

46      41.2

46      42.4

56.8     52

61.6      58.4

63.6     63

65      62

65      64.4

65.6     63

69        65

Once the table is obtained, we proceed to do the following.

Once this table is obtained, it is necessary to find two additional values from it  and x * y. At the end of obtaining the values we will make a sum of each of the columns: Sum of X, Y, and x *y and at the bottom of our table, so this is obtained:

X      Y      x2       x*y

45    39.420251773

46    41.221161895.2

46    42.421161950.4

56.8    52       3226.242953.6

61.6    58.43794.563597.44

63.6    634044.964006.8

65       6242254030

65    64.442254186

65.6    634303.364132.8

69      6547614485

583.6   550.8   34837.12   33010.24*

*Values in italics are the sum of each of the columns.

** It is difficult to add this table here, I will add it as an attachment.

The approximation equation is first degree, so we apply the formula:

Y = mx + b

Where m is given by the equation:

Where n is the total number of data, In our case n=10,

So we replace the values we have and get the following value from m:

So,

On the other hand to find the value of b, we apply the following formula:

So,

Then,

Thus once m and b are obtained, we have the equation of the line, where:

2) To perform the Residual Test we simply take two values from the Table in X and replace

 -

Thus

(an intermediate value and quite well approximate for any of the first two values of our table)

-

So

 (A value very close to that of our penultimate table data)

3)  With the high reliability of our equation we can solve this point, thus our new value for

So that

Our person will have a height of 64.1

4) We now perform the replacement for 74 inch, but for the value of Y,

So that

The length of his arms is 74.84 inch