Find the linear function that is the best fit for the data.

| [tex]\( x \)[/tex] | 1 | 3 | 5 | 7 | 9 |
|:--------:|---|---|---|---|---|
| [tex]\( y \)[/tex] | 4 | 9 | 14 | 19 | 24 |

What is the linear function of the data?

[tex]\( y = 2.5x + 1.5 \)[/tex]

(Type integers or decimals.)



Answer :

Certainly, let's walk through the process of finding the best fit linear function for the given data step-by-step.

### Given Data Points:
[tex]\[ \begin{array}{|c|c|c|c|c|c|} \hline x & 1 & 3 & 5 & 7 & 9 \\ \hline y & 4 & 9 & 14 & 19 & 24 \\ \hline \end{array} \][/tex]

### Steps to Find the Linear Function:
1. Calculate the Mean of [tex]\( x \)[/tex] and [tex]\( y \)[/tex]:

[tex]\[ \bar{x} = \frac{1 + 3 + 5 + 7 + 9}{5} = \frac{25}{5} = 5 \][/tex]
[tex]\[ \bar{y} = \frac{4 + 9 + 14 + 19 + 24}{5} = \frac{70}{5} = 14 \][/tex]

2. Compute the Slope (m) of the Line:

We use the formula for the slope [tex]\( m \)[/tex]:
[tex]\[ m = \frac{\sum (x_i - \bar{x})(y_i - \bar{y})}{\sum (x_i - \bar{x})^2} \][/tex]

Calculate the individual components:

[tex]\[ \sum (x_i - \bar{x})(y_i - \bar{y}) = (1 - 5)(4 - 14) + (3 - 5)(9 - 14) + (5 - 5)(14 - 14) + (7 - 5)(19 - 14) + (9 - 5)(24 - 14) \][/tex]
[tex]\[ = (-4)(-10) + (-2)(-5) + (0)(0) + (2)(5) + (4)(10) \][/tex]
[tex]\[ = 40 + 10 + 0 + 10 + 40 = 100 \][/tex]

[tex]\[ \sum (x_i - \bar{x})^2 = (1 - 5)^2 + (3 - 5)^2 + (5 - 5)^2 + (7 - 5)^2 + (9 - 5)^2 \][/tex]
[tex]\[ = (-4)^2 + (-2)^2 + (0)^2 + (2)^2 + (4)^2 \][/tex]
[tex]\[ = 16 + 4 + 0 + 4 + 16 = 40 \][/tex]

So, the slope [tex]\( m \)[/tex]:
[tex]\[ m = \frac{100}{40} = 2.5 \][/tex]

3. Compute the Y-intercept (b):

The y-intercept [tex]\( b \)[/tex] is found using the formula:
[tex]\[ b = \bar{y} - m \bar{x} \][/tex]

Substitute the values we have:
[tex]\[ b = 14 - 2.5 \times 5 \][/tex]
[tex]\[ b = 14 - 12.5 \][/tex]
[tex]\[ b = 1.5 \][/tex]

### Linear Function of the Data:
Given the slope ( [tex]\( m = 2.5 \)[/tex] ) and the y-intercept ( [tex]\( b = 1.5 \)[/tex] ), the linear function that best fits the data is:
[tex]\[ y = 2.5x + 1.5 \][/tex]

So, the best fit linear function is:
[tex]\[ y = 2.5x + 1.5 \][/tex]