This is really a problem of evaluation of functions.
As indicated, for year
2000, x=1, so for
2008, x=2008-1999=9, and for
2010, x=2010-1999=11
Let
y = f(x) = 90+0.9x+3x²
for 2000, f(1) = 90 + 0.9*(1) + 3*1² = 93.9
for 2008, f(9) = 90 + 0.9*(9) + 3*9² = 341.1
for 2010, f(11)= 90 + 0.9*(11) + 3*11² = 462.9
Note that in general, the number of repairs is an integer (whole number), so the estimate should be rounded to the nearest integer.
An appliance repair shop owner has fitted the quadratic trend equation ŷ = 90 + 0.9x + 3x² to a time series of annual repair orders, with y= the number of repair orders and x= 1 for 2000. Forecast the number of repair orders for 2008; for 2010
1 answer
1 answer