For questions 1 through 3 state the proper t-test (one sample, paired samples, independent samples) that should be used to evaluate the research question: (*Just state the test)

1) A developmental psychologist wants to determine if a recently created computer training program can increase the working memory ability of high-school students. A sample of 40 students are given the reverse digit span test at the beginning of the school year and then again after 4 weeks of training. Are there significant changes from pre- to -post?

2) A representative from Pepsi believes that Pepsi is a better testing soda than Coca-Cola and wants to test this officially. At an FAU tailgate 40 students are invited to participate in a taste testing. Twenty students are asked to rate how much they like Pepsi on a scale of 1-10 and the other 20 are asked to rate how much they like coca cola? Is the mean score significantly higher for the Pepsi group or the Coca-Cola group?

3) The national average GRE score on the math section is a 136. A graduate coordinator would like to determine if a sample of 20 students who applied to graduate school at FAU score significantly different from average.

Complete an independent samples t-test for the following example: Are the exam scores higher for group 1 (Freshman) compared to group 2 (Sophomores). Each group contains 30 students.

Group 1: Mean score 94, variance of 100

Group 2: Mean score 98, variance of 110

4a. Provide the standard deviation of the distribution of differences between means

4b. Provide the t-score and critical t-value

4c. Are the exam scores significantly different between groups?