(a) Develop an estimated multiple regression equation that relates risk of a stroke to the person's age, systolic blood pressure, and whether the person is a smoker. Let x1 represent the person's age. Let x2 represent the person's systolic blood pressure. Let x3 represent whether the person is a smoker. If required, round your answers to three decimal places. For subtractive or negative numbers use a minus sign even if there is a + sign before the blank. (Example: -300) = + X1 + X2 + X3