In an area of Russia, records were kept on the relationship between the rainfall (in inches) and the yield of wheat (bushels per acre). The data for a 9 year period is as follows: The equation of the line of least squares is given as = -9.12 + 4.38x.
- How many bushels of wheat per acre can be predicted if it is expected that there will be 30 inches of rain?
A) Cannot be certain of the result because 30 inches of rain exceeds the observed data.
B) 8.93
C) 122.28
D) 140.52

Question

In an area of Russia, records were kept on the relationship between the rainfall (in inches) and the yield of wheat (bushels per acre). The data for a 9 year period is as follows:  The equation of the line of least squares is given as  = -9.12 + 4.38x.
- How many bushels of wheat per acre can be predicted if it is expected that there will be 30 inches of rain?
A) Cannot be certain of the result because 30 inches of rain exceeds the observed data. 
B) 8.93 
C) 122.28 
D) 140.52

Quizplus · Accepted Answer

The prediction cannot be made with certainty if the given amount of rain (30 inches) exceeds the range of data observed or used to create the predictive model. Without specific details on the model or its range, the safest assumption is that predictions outside the observed data range are unreliable.

In an Area of Russia, Records Were Kept on the Relationship