To approximate the earnings in 1999 using the given equation \( y = 0.497x - 973.9 \), we need to substitute \( x \) with the year 1999.
First, we determine the value of \( x \) corresponding to the year 1999. Since the equation appears to use 1996 as a base year (i.e., \( x = 0 \) corresponds to 1996), we calculate \( x \) for 1999 as follows:
\[ x = 1999 - 1996 = 3 \]
Now, we substitute \( x = 3 \) into the equation:
\[ y = 0.497(3) - 973.9 \]
Calculating \( 0.497(3) \):
\[ 0.497 \times 3 = 1.491 \]
Now we can plug that back into the equation:
\[ y = 1.491 - 973.9 \]
Calculating the result:
\[ y = 1.491 - 973.9 = -972.409 \]
Thus, the model predicts that the average hourly earnings of production workers at Nussbaum Steel in 1999 would be approximately \(-972.409\).
However, this result suggests that our formula may not be providing a realistic output for the time period given that average hourly earnings cannot be negative. Please recheck the parameters or consider if there is a different contextual or interpretive framework for this equation. Nonetheless, according to the calculation with the provided formula, that's the outcome.