Final answer:
To determine which line better represents the data, Y=0.6X or Y=0.5X, an R-squared value needs to be calculated for both.
Step-by-step explanation:
The question asks which linear equation better represents the temperature increase in the State of Michigan from January to June: Y=0.6X or Y=0.5X, based on the given data points. To find which line has the greater R-squared value, we would need to calculate the sum of squares of the vertical distances of the data points from both lines and compare these sums. However, without having the option to actually calculate the R-squared values here, we can visually inspect the data and the equations to gauge which might more closely fit the data points.
Visually estimating based on the temperatures on days 1, 25, 46, 76, and 140, we can observe that the temperatures appear to increase at a rate that may be closer to 0.6 degrees Fahrenheit per day rather than 0.5 based on the last data point (140,77), which suggests a steeper increase than what Y=0.5X would predict. Nevertheless, without performing the full regression analysis, this estimation is not definitive. A proper R-squared calculation would provide the answer numerically and accurately.