To find the slope and y-intercept of the line that best fits the given data, we will use the least squares regression method.
Step 1: Calculate the means of x and y:
\bar{x}=\frac{1}{n}\sum_{i=1}^nx_i=\frac{4+5+6+7+8+9+10+11+12+13+14+15}{12}=9.5
\bar{y}=\frac{1}{n}\sum_{i=1}^ny_i=\frac{10.96+10.1+9.94+9.68+9.42+9.16+10.8+9.64+11.58+10.22+12.36+13}{12}=10.5717
Step 2: Calculate the slope:
m = \frac{\sum_{i=1}^{n} (x_i - \bar{x})(y_i - \bar{y})}{\sum_{i=1}^{n} (x_i - \bar{x})^2}
\sum_{i=1}^n(x_i-\bar{x})(y_i-\bar{y})=(4-9.5)(10.96-10.5717)+\cdots+(15-9.5)(13-10.5717)=28.27
\sum_{i=1}^n(x_i-\bar{x})^2=(4-9.5)^2+(5-9.5)^2+\cdots+(15-9.5)^2=143
m=\frac{28.27}{143}\approx0.1977
Step 3: Calculate the y-intercept:
b=\bar{y}-m\bar{x}=10.5717-(0.1977\times9.5)\approx8.6936
Therefore, the equation of the line that best fits the data is y=0.1977x+8.6936 .
Answer: The slope is 0.1977 and the y-intercept is 8.6936.