Scatter plot has one dot for each data point. Create a graph with the known variable along the x axis and the dependent variable along the y axis. In this case latitude for a city is unchanging so it belongs on the x axis. Temperature on the y axis. Use the highest and lowest value from each list to determine the scale 25 to 45 latitude and 32 to 76 degrees temp. So I chose 25 to 50 for latitude and 30 to 80 for temperature. Plot the points on the graph. I labeled them for clarity but this is not a necessary feature of a scatter plot. Then you use the assigned method to determine the slope and intercept of the trend line. I used Excel. You can use a scientific calculator or the pencil/paper algorithm. The slope is -2.48. Which means that change of +1 latitude results in lower temperature by 2.48 F
At latitude zero, expected temp is 137. This highlights the problem of extrapolation, which is a side issue. Plugging latitude 50 into the resulting equation yields 13.6 degrees F. NB both latitude and temperature are measured in “degrees” but these are vastly different. I left the unit off latitude to avoid this confusion.
