A school newspaper article claims that the mean weight of student backpacks is 20 pounds. A student of this school would like to test the hypotheses = 20 versus 20 where μ = the true mean weight of all backpacks using a random sample of 30 students. The power of this test to reject the null hypothesis when μ = 19.5 is 0.78 when a significance level of 0.05 is used. Which of the following would increase the power of this test?