nvestors are always reviewing past pricing history and using it to influence their future investment decisions. On May 16, 2014, online car buying system TrueCar launched its initial public offering (IPO), raising $70 million in the stock offering. An investor, looking for a promising return, analyzes the monthly stock price data of TrueCar from June 2014 to May 2017. A portion of the data is shown in the accompanying table.

Date	Price
June-14	14.78
July-14	13.57
May-17	17.51

Click here for the Excel Data File

Date	Price
June/14	14.78
July/14	13.57
August/14	20.67
September/14	17.95
October/14	16.80
November/14	19.16
December/14	22.90
January/15	17.58
February/15	19.90
March/15	17.85
April/15	15.42
May/15	13.83
June/15	11.99
July/15	6.52
August/15	5.44
September/15	5.21
October/15	6.14
November/15	8.03
December/15	9.54
January/16	6.48
February/16	5.43
March/16	5.59
April/16	6.84
May/16	7.59
June/16	7.85
July/16	9.37
August/16	9.65
September/16	9.44
October/16	9.65
November/16	12.38
December/16	12.95
January/17	13.15
February/17	14.06
March/17	15.47
April/17	17.52
May/17	17.51

a. Estimate the linear, the quadratic, and the cubic trend models. (Negative values for regression coefficients should be indicated by a minus sign. Round your answer to 3 decimal places.)

b-1. Determine the preferred model.

b-2. Use the preferred model to make a forecast for June 2017. (Do not round coefficient estimates. Round final answers to 2 decimal places.)