11.44 An employer has found that factory workers who are with the company longer tend to invest more in a company investment program per year than workers who have less time with the company.

The following model is believed to be adequate in modeling the relationship of annual amount invested Y to years working for the company x:

The employer checks the records for a sample of 50 factory employees for a previous year and fits the above model to get and

. The basic shape of a quadratic model depends upon whether or .

Test to see whether the employer can conclude that .Use .