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How do you think you did on the exam?

A researcher is interested in whether exercise improves memory. The researcher randomly selects 100 participants, assigns them to an exercise programs and measures memory at the end of the exercise program. The population mean on the memory test is 25. How should the null hypothesis be stated for a directional, one sample t test?

A researcher wants to determine if there are differences in anxiety scores based on pet ownership status. He asked students to complete the Generalized Anxiety Disorder Questionnaire (GAD) and then to classify their pet ownership as do not own a pet, own a dog, or own a cat. Assuming α = .05, choose the correct decision.  

A sample of n = 5 scores produces a t statistic of t = + 3.75. What is the value of the effect size, r2?  (round to 2 decimal places)

With α = .05, the two-tailed critical region for a t test using a sample of n = 25 participants would have boundaries of _____.  

A researcher computes a one-way ANOVA and collects the following data: M1 = 24   M2= 29   M3 = 11      q = 3.5     MSerror = 80.5    n= 4 Compute Tukey’s HSD  post-hoc test and state which mean pairs are significant?

Researchers are comparing the effect a relaxation intervention on final exam scores in a sample of 200 high school students. A hundred students completed a relaxation class before their final exam while the other 100 students do not receive any intervention before the final. The students complete the final exam and researcher records the final exam scores. What type of t test is appropriate for this study? 

The department of psychology researchers are interested whether tutoring improves student performance in PSY 3204. They examined differences in final grades of students who attended tutoring sessions vs. those who did not and found that the average course grades were 79 and 75, respectively. Use the results of 95% CI below to determine whether tutoring significantly improved grades in PSY 3204. The researchers should make the decision to [reject] the null hypothesis and conclude that final grades in PSY 3204 were [significantly] higher among students who were tutored as compared to those who were not.  (Hint: state the decision and whether the result was significant or not significant)

Two researchers (A and B) compute a one-sample t test. For both tests, the standard error is the same, but the mean difference between the sample and value stated in the null hypothesis is smaller for Researcher A. Which test is more likely to result in a decision to reject the null hypothesis?

A researcher conducts an independent sample t test and obtains the value of t(49) = 0.567 and the critical value of ±2.320. What is the correct decision to take based on these data?