Part 4: A one-sample t-test using JASP.

You believe that listening to classical music can help brain function. To test this, you select a random sample of students to take a test where the average score is 85 in the population. You have students take the test while listening to music, and you think their average score will be higher than average. Test your hypothesis with alpha level of .05. Write the hypotheses in words and include the population value.

17. Is this a one-tailed or two-tailed t-test?__

18. Null hypothesis: __

19. Alternative hypothesis: __

20. Find the Critical value for t (consult t-table, use =.05, 1-tailed, (df =n-1 = __) critical t = ______

Enter the following test scores:

95, 97, 80, 78, 93, 64, 98, 85, 79, 85, 87, 73, 96, 95, 94,

97, 99, 85, 95, 93, 87, 88, 95, 80, 85, 95, 93, 64, 80, 85, 86, 87, 99, 99, 84, 93, 92, 91, 93, 64

Save as a csv file, then open your csv file in JASP.

Run Descriptive Statistics on the DV. Add skew & kurtosis, and a density plot, to check normality.

21. Record the following values for the sample:

Sample size (Valid n) = ______ Sample mean = ________ Sample SD = _______

Run a One-Sample t-test (click on T-Tests, classical, one-sample t, Student, move DV to variables box, enter the test value = 85 (this is the pop mean), in Alt Hyp: select > Test value because you predicted an increase in DV.

22. Record the values from the JASP results t-table: t = ______ df = _____ p = ________

• Add Descriptives to the one-sample t-test so we can calculate it by hand also as we did the others.

a. Mean difference (Sample mean - Population mean) = __________________

b. Estimated standard error from JASP SE = _____________

c. t-score by hand (Mean difference / Standard Error) t = ______________________

23. Decision: Is the calculated t-score greater than the critical t-score? Can we reject the null hypothesis? ____

24. Based on these results, write APA conclusion about the effect of classical music on test scores.

______________________________________________________________________________________

25. What if we ran a two-tailed test? Change the Alt Hyp to . What is the p-value now?___

Is it significant? ___ Is it easier to find significance with a 1-tailed or 2-tailed test? ________