Using a sample of recent college graduates, Dr. Harrison performs a regression analysis to study the effect of extracurricular activities in college on starting salary in the first job. Her independent variables include (x1) number of campus organizations in which the student was a member, (x2) number of organizations in which the student was an officer, and (x3) number of hours per week devoted to extracurricular activities. She finds that none of these variables is statistically significant. Is she safe in concluding that extracurriculars have no impact on starting salaries? Explain why or why not.