In a study to test the effects of marijuana use on mental abilities, groups of light and heavy users of marijuana in college were tested for memory recall. There were 64 light users and 62 heavy users. The mean number of items correctly sorted from memory were found for each group. Light users correctly sorted a mean of 53.3 items, with a sample SD of 3.6. Heavy users correctly sorted a mean of 51.3, with a 2 sample SD of 4.5. Use a 0.01 significance level to test the claim that the population of heavy marijuana users has a lower/worse memory recall than light users.