Researchers claim that herbal supplements such as ginseng or ginkgo biloba enhance human memory.
To test this claim, a researcher selects a sample of n = 25 college students. Each student is given a ginkgo biloba supplement daily for six weeks and then all the participants are given a standardized memory test. For the population, scores on the test are normally distributed with ? = 70 and ? = 15. The sample of n = 25 students had a mean score of M = 75. Are the data sufficient to that the herb has a significant effect on memory? Use a two-tailed test with ? = .05.
Provide the z value you find in calculation (calculated z), the critical z that you compare it with and how you obtained it, and if you reject or retain the null in this instance