Rounding to three decimal places, the slope is approximately -1.892 and the y-intercept is approximately 31.931. Therefore, the equation for the line of best fit is closest to: c. y = -1.893x + 31.901
To find the equation for the line of best fit, we'll use the least squares method to calculate the slope (m) and y-intercept (b).
Given data:
X: 2, 5, 7, 12, 16
y: 30, 19, 20, 9, 2
Let's first calculate the means of X and y:
![\[ \bar{X} = (2 + 5 + 7 + 12 + 16)/(5) = (42)/(5) = 8.4 \]](https://img.qammunity.org/2023/formulas/mathematics/college/fxiaxa0cll763o3s6r4nn3fupqx26vbtqq.png)
![\[ \bar{y} = (30 + 19 + 20 + 9 + 2)/(5) = (80)/(5) = 16 \]](https://img.qammunity.org/2023/formulas/mathematics/college/ma72hfbc917swl8eo3c70oxhekq79hl2nn.png)
Now, let's calculate the slope (m) using the formula:
![\[ m = \frac{\sum_(i=1)^(n) (x_i - \bar{X})(y_i - \bar{y})}{\sum_(i=1)^(n) (x_i - \bar{X})^2} \]](https://img.qammunity.org/2023/formulas/mathematics/college/u7fir4thiaa6l08cuyp4ln4mxclk9994g5.png)
Calculating the numerator and denominator:
Numerator:
![\[ (2 - 8.4)(30 - 16) + (5 - 8.4)(19 - 16) + (7 - 8.4)(20 - 16) + (12 - 8.4)(9 - 16) + (16 - 8.4)(2 - 16) \]](https://img.qammunity.org/2023/formulas/mathematics/college/3wcib1wwnwh08ftazitb4mkbtf600cfnfo.png)
![\[ (-6.4)(14) + (-3.4)(3) + (-1.4)(4) + (3.6)(-7) + (7.6)(-14) \]](https://img.qammunity.org/2023/formulas/mathematics/college/dhugu8uja1eb3d97lm2g8vrm8sr6c1aqzz.png)
![\[ -89.6 - 10.2 - 5.6 - 25.2 - 106.4 = -237 \]](https://img.qammunity.org/2023/formulas/mathematics/college/8abp83sop1gxm2ovejuoo3k420urlm55zg.png)
Denominator:
![\[ (2 - 8.4)^2 + (5 - 8.4)^2 + (7 - 8.4)^2 + (12 - 8.4)^2 + (16 - 8.4)^2 \]](https://img.qammunity.org/2023/formulas/mathematics/college/ysip459hwx7vqi0w7cbtr4lfnx3sk7bdxo.png)
![\[ (-6.4)^2 + (-3.4)^2 + (-1.4)^2 + (3.6)^2 + (7.6)^2 \]](https://img.qammunity.org/2023/formulas/mathematics/college/yykvdtfuy665gxdbxbnd3glujbxk63zlan.png)
![\[ 40.96 + 11.56 + 1.96 + 12.96 + 57.76 = 125.2 \]](https://img.qammunity.org/2023/formulas/mathematics/college/11k15iw88ghn0z68c4d5han7mu4zgklrib.png)
Now, let's calculate the slope m:
![\[ m = (-237)/(125.2) \approx -1.892 \]](https://img.qammunity.org/2023/formulas/mathematics/college/m664121dkk8j3fd5k0cg4zyoi70igng9ha.png)
Next, let's calculate the y-intercept b using the formula:
![\[ b = \bar{y} - m * \bar{X} \]](https://img.qammunity.org/2023/formulas/mathematics/college/q85hivop6506kyzp7uh0yxd6wbwvkr9j9v.png)
![\[ b = 16 - (-1.892) * 8.4 \]](https://img.qammunity.org/2023/formulas/mathematics/college/35f5fjntru2o4b4ee5ljgxfng9xo0z2gpa.png)
![\[ b = 16 + 15.931 \]](https://img.qammunity.org/2023/formulas/mathematics/college/de57sh18a4lwahbmlm83i63vx95rmqp3q6.png)
![\[ b \approx 31.931 \]](https://img.qammunity.org/2023/formulas/mathematics/college/t60zy94lee2srgjgpncb460gjzjvtdrxaj.png)
Rounding to three decimal places, the slope is approximately -1.892 and the y-intercept is approximately 31.931. Therefore, the equation for the line of best fit is closest to option: c. y = -1.893x + 31.901