The accurate answers are:
y = 0.10x + 2.50; $5.
Exposition:
Employing a graphing calculator, input the data via the STAT function. The year will represent the independent (x) variable, while the cost will serve as the dependent (y) variable.
Instead of starting at 1998 for the year, we begin at 0, as that is our baseline. Consequently, the year 2000 will correspond to 2; 2002 will be 4; and so on, up to x=10.
Upon running the linear regression, the calculator yields a slope of 0.10 and a y-intercept of 2.499, rounded to 2.50. Thus, the equation is y = 0.10x + 2.50.
To estimate the price in 2023, we must first calculate our x-value. This is done by subtracting 1998 from the current year:
2023-1998 = 25
Now we substitute 25 for x in the equation:
y = 0.10(25) + 2.50 = 2.50 + 2.50 = 5