to test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. if we are testing at the 5% significance level to see whether the business school preparation course is effective in improving exam scores, our critical value is 1.895. suppose that we have decided to reject the null. the conclusion is that there is sufficient evidence that course does improve exam score there is sufficient evidence that the course does not improve exam score there is sufficient evidence that the course has no impact on exam score no conclusion can be drawn from the information given