Linear Regression Caaccd
1. **Problem Statement:**
We are given sums and means of two variables $x$ (catalyst amount) and $y$ (chemical process yield) and need to analyze their relationship, likely by finding the linear regression line.
2. **Given Data:**
- $\sum x_i = 13.8$
- $\sum y_i = 523.3$
- $\sum x_i y_i = 911.58$
- $\sum x_i^2 = 25.16$
- $\sum y_i^2 = 34356.85$
- $\bar{x} = 1.725$
- $\bar{y} = 65.412$
3. **Formula for Linear Regression Line:**
The regression line of $y$ on $x$ is given by:
$$y = a + bx$$
where
$$b = \frac{\sum (x_i y_i) - n \bar{x} \bar{y}}{\sum (x_i^2) - n \bar{x}^2}$$
$$a = \bar{y} - b \bar{x}$$
4. **Calculate $n$ (number of data points):**
Since $\bar{x} = \frac{\sum x_i}{n}$, then
$$n = \frac{\sum x_i}{\bar{x}} = \frac{13.8}{1.725} = 8$$
5. **Calculate slope $b$:**
$$b = \frac{911.58 - 8 \times 1.725 \times 65.412}{25.16 - 8 \times (1.725)^2}$$
Calculate numerator:
$$911.58 - 8 \times 1.725 \times 65.412 = 911.58 - 902.68 = 8.9$$
Calculate denominator:
$$25.16 - 8 \times 2.976 = 25.16 - 23.81 = 1.35$$
So,
$$b = \frac{8.9}{1.35} \approx 6.59$$
6. **Calculate intercept $a$:**
$$a = 65.412 - 6.59 \times 1.725 = 65.412 - 11.36 = 54.05$$
7. **Final regression equation:**
$$y = 54.05 + 6.59x$$
This means for each additional liter of catalyst, the yield increases by approximately 6.59%.