18. A group of Industrial-Organizational psychologists wanted to test if giving a motivational speech at the end of a meeting would have any effect on their work based on the number of sales each worker made. The researchers used the same 10 workers in both conditions: first data were collected after a regular meeting with no speech, and later after a meeting ending with a motivational speech. Calculate the change in sales using T2 - T1. Here are the sales numbers for the 10 participants in both conditions. Use the four steps of hypothesis testing to find out if the motivational speech had any effect on sales using the appropriate t-test.

a. State the null and alternative hypotheses. Is it 1 tailed or 2?

b. Find the critical value for this t-test. Which tail is shaded?

c. Perform a related-samples t-test.

d. Is there a significant mean difference across conditions? Test using an alpha level of .05. Write your conclusion using @P@ format (test used, significance, include IV and DV, APA stats and direction of any significant difference found.)

e. Enter these data and run the repeated-t test in JASP. This time make it a one-tailed test - predicting an increase in sales. Include location parameter (to get the MD) and the effect size (Cohens d). Copy the significance table into your HW. Write the @P@ conclusion again including from the JASP results the exact p-value for your test, the mean difference, and the effect size d.

Motivational speech T2 = 4 5 8 7 2 11 9 3 4 10

No speech T1 = 2 1 4 9 0 9 2 3 7 3