Step 1 :First, we need to understand that the question is asking for the predicted well-being index score for a person whose commute time is 25 minutes.
Step 2 :From the given data, we know that for a commute time of zero minutes, the index score is predicted to be 68.995.
Step 3 :We also know that for every unit increase in index score, the commute time falls by a certain amount, but this amount is not given in the question.
Step 4 :However, we can use the given data to find the rate of change of the index score with respect to the commute time.
Step 5 :From the data, we can see that as the commute time increases, the index score decreases. This suggests a negative correlation between the two variables.
Step 6 :Let's assume that the rate of change of the index score with respect to the commute time is constant. Then, we can use the formula for the slope of a line to find this rate.
Step 7 :The slope of a line is given by the change in the y-values divided by the change in the x-values. In this case, the y-values are the index scores and the x-values are the commute times.
Step 8 :Using the first and last data points, we find that the slope is (606 - 690) / (105 - 5) = -0.84.
Step 9 :This means that for every unit increase in commute time, the index score decreases by 0.84.
Step 10 :Now, we can use this rate to predict the index score for a commute time of 25 minutes.
Step 11 :We start with the index score for a commute time of zero minutes, which is 68.995, and subtract the product of the commute time and the rate of change.
Step 12 :This gives us 68.995 - 25 * 0.84 = 48.995.
Step 13 :So, the predicted well-being index score for a person whose commute time is 25 minutes is \(\boxed{48.995}\).