EDUC 5313 Fall 2015, Problem Set 3: Instructions: You may print out this page and write your answers on this sheet. Do not forget to write down your name and the time it took you to complete this assignment at the bottom of this page. 1. Some 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. 2. A sample of n = 16 individuals is selected from a population with = 30. After a treatment is administered to the individuals, the sample mean is found to be M = 33. a. If the sample variance is s2 = 16, then calculate the estimated standard error and determine whether the sample is sufficient to conclude that the treatment has a significant effect? Use a two-tailed test with = .05. b. If the sample variance is s2 = 64, then calculate the estimated standard error and determine whether the sample is sufficient to conclude that the treatment has a significant effect? Use a two-tailed test with = .05. c. Describe how increasing variance affects the standard error and the likelihood of rejecting the null hypothesis. 3. A psychologist is examining the educational advantages of a preschool program. A sample of 24 fourth grade children is obtained. Half of these children had attended preschool and the others had not. The psychologist records the scholastic achievement score for each child and obtained the following data: Preschool 8 9 6 9 6 7 9 7 8 7 8 8 No preschool 8 6 7 7 5 8 5 5 7 5 6 6 Enter the data into PSPP and conduct an independent samples t-test. Attach the resulting output to your homework. [Hint: data entry was described in detail in problem set 2; Getting to the independent-samples t-test menu: 1. Select Analyze from the top tool bar. 2- From the Analyze drop down menu, select Compare Means. 3. From the Compare Means side pop-up menu, select Independent Samples T Test... Sample video https://www.youtube.com/watch?v=COsNrNo53bI ] Name: __________________________ Time it took to complete problem set 3: __________________ (minutes)