Final answer:
To make a line of best fit, draw a scatter plot, then draw a line that best represents the trend of the data. Calculate the slope and y-intercept by choosing two points on the line. The equation of the line will have the form y = mx + b, where m is the slope and b is the y-intercept.
Step-by-step explanation:
To make a line of best fit, you first need to draw a scatter plot of your data. Then you'll use a straight edge to draw a line that represents the general direction the points seem to be taking. This line doesn't need to go through all the points, but should distribute them fairly evenly on both sides. To calculate the slope and y-intercept of the line of best fit, start by picking two points on the line that are easy to read off the graph. Label these points (x1, y1) and (x2, y2).
To find the slope (represented by 'm'), use the formula m = (y2 - y1) / (x2 - x1). The slope describes how the dependent variable changes for a one-unit increase in the independent variable. After calculating the slope, you find the y-intercept (represented by 'b') by extending the line till it crosses the y-axis. The y-axis value where it crosses is the y-intercept. The equation of the line of best fit would then be y = mx + b.
An r value of zero indicates that there is no linear correlation between the two variables.