You are given the following regression results estimating the demand for widgets based on time series data for the past 40 months.
Qt = 2.5 - 0.3 x Pt + 12 x Mt
Where Qt represents the quantity of widgets sold per period t, Pt represents the price of widgets during period t, and Mt represents average household income of customers during period t.
You are also given the following information about the regression results
R2 = 0.75 F-statistic = 23 Durbin-Watson (d) statistic = 0.66
standard deviation of constant = 0.52; standard deviation of P = 0.16
standard deviation of M = 2.0
Which of the independent variables are statistically significant at the 5% level?