A researcher claims that on average , high school students sleep less than middle school students . The researcher recorded the sleeping times of 49 middle school students and 55 high school students . For the middle school students , the mean daily time asleep was hours with standard deviation 0 2 For the high school students , the man daily time asleep was 7.9 hours with standard deviation 5 hours Condict two - sample - test to test the researcher claim on the 5 level