Questions: For the following data set:
(a) Compute the least-squares regression line. Round the answers to at least four decimal places.
Regression line equation:
(b) Which point is an outlier?
For the following data set:
(a) Compute the least-squares regression line. Round the answers to at least four decimal places.
Regression line equation:
(b) Which point is an outlier?
Solution
Solution Steps
To solve the problem, we need to compute the least-squares regression line for the given data set and identify any outliers. Since the data set is not provided, I'll outline the steps you would take to solve this problem once you have the data.
Step 1: Gather the Data
First, collect the data points that you will use to compute the regression line. The data should be in the form of pairs (x, y).
Step 2: Calculate the Means
Calculate the mean of the x-values (\(\bar{x}\)) and the mean of the y-values (\(\bar{y}\)).
Step 3: Compute the Slope (b1)
Use the formula for the slope of the regression line:
\[ b_1 = \frac{\sum{(x_i - \bar{x})(y_i - \bar{y})}}{\sum{(x_i - \bar{x})^2}} \]
Step 4: Compute the Intercept (b0)
Calculate the y-intercept of the regression line using the formula:
\[ b_0 = \bar{y} - b_1\bar{x} \]
Step 5: Formulate the Regression Line Equation
Combine the slope and intercept to form the regression line equation:
\[ y = b_0 + b_1x \]
Step 6: Identify Outliers
Examine the data points to identify any that do not fit the pattern of the rest of the data. A common method is to look for points that have a large residual (the difference between the observed y-value and the predicted y-value from the regression line).
Final Answer
Once you have the regression line equation and have identified any outliers, you can present your final answer. The regression line equation will be in the form \( y = b_0 + b_1x \), and you will specify which point, if any, is an outlier.