In this specific case, you cannot choose arbitrary points. The exam instructions explicitly state to "Use the last two samples from the dataset" to perform the calculations.
The student followed this by selecting the values from the final rows of Table 2:
The prompt requires you to show mathematical calculations for deriving coefficients using those specific samples. Using different IDs (like 1 or 2) would result in a loss of marks for failing to follow the constraint.
The linear component of the model z = a0 + a1x has two unknowns.
To solve for these, you need two distinct data points:
a1 = (4.61 - (-4.6)) / (5.5 - 6.0).
Only focusing those that seem like Chapter 3 - 5 (coverage for test)