If the coefficient β1 has a non-zero value, then it is helpful in predicting the value of the response variable. If β1 = 0, it is not helpful in predicting the value of the response variable and can be eliminated from the regression equation. To test the claim that β1 = 0 use the test statistic t = (b1 — 0)/sb1. Critical values or P-values can be found using the t distribution with n — (k + 1) degrees of freedom, where k is the number of predictor (x) variables and n is the number of observations in the sample. The standard error sb1 is often provided by software. For example, the Minitab display in Example 1 shows that sb1 = 0.1289. Use the sample data in Table 10-4 and the Minitab display in Example 1 to test the claim that β1 = 0. Also test the claim that β2 = 0. What do the results imply about the regression equation?