Final answer:
To create a line of best fit, plot the data points on a scatter plot and draw a line that reflects the trend. Calculating the slope requires two points on the line, and the y-intercept is where the line crosses the y-axis. The slope shows how y changes with each unit increase in x, and an r-value of zero indicates no linear relationship.
Step-by-step explanation:
To create a line of best fit for a set of data points, you must first plot the data on a scatter plot. After graphing, use a straight edge to draw a line that best represents the trend of the points. The line does not have to pass through all the points but should have roughly equal numbers of points above and below it. This line is a visual representation of the average trend in the data.
To calculate the slope, choose two points on the line of best fit. The slope (slope) is the rise over the run, which is the change in the y values divided by the change in the x values. The y-intercept is the point where the line crosses the y-axis. To find this, extend the line to the y-axis and record its value (y-intercept).
The slope of the line tells us how the dependent variable (y) changes for every unit increase in the independent variable (x), on average. The y-intercept represents the value of y when x is zero. For instance, the predicted height for a given pinky length would be calculated using the line's slope and y-intercept from the equation of the line.
An r value of zero means that there is no discernible linear relationship between the two variables.