Title: Assignment: OA 8 t-test
Course: PSYC 301 Statistical Methods in Psychol

For this OA you will use jamovi for a t-test.

The problem is one using real data about testosterone changes in sports spectators.

Eight males were approached at a basketball game and asked to provide saliva samples before and after a game. There were four supporters of each team.  One team won the game, of course. So, one set of fans had supported the winning team. Testosterone was measured in the saliva before and after and that yielded a change in testosterone score for each fan. That is, some fans had their testosterone increase (positive values), others had it decrease (negative values) Those change scores are what we will analyze.

Based on Basking in Reflected Glory, we are aware that people feel an increase in social status or dominance due to the outcomes of their favored sports teams. From other studies we know a sense of increased social status or dominance is associated with higher testosterone.

Therefore, we hypothesized that testosterone would increase for spectators who supported the winning team compared to those who supported the losing team.

First, do download the jamovi file, then do the steps for completing the assignment. After that answer the questions further below to complete the assignment.

Click to download the jamovi file.

Open jamovi and load the file into it.

- This is what the variables mean
  - Participant is simply a participant identification number
  - Status is the winning or losing status of each participant, this variable divides them into groups
  - Testo_Change is the change in testosterone from before to after the game. Positive numbers mean an increase in testosterone, negative numbers mean a descrease in testosterone.

You will be doing an independent samples t-test.

To do this in jamovi follow these steps:

1. Select Analyses tab
2. Select T-Tests item (second from left)
3. In the drop down, select Independent Samples T-Test
4. The Dependent Variable is Testo_Change
5. The Grouping Variable is Status.
6. Confirm the following are correctly set:
  - Under Tests, only Student's  should be checked.
  - Under Hypotheses only Group 1 ≠ Group 2 should be marked
  - Under Additional Statistics only Descriptives should be checked.
  - Under Assumption Checks, nothing should be checked.
7. Your output will have the following:
  - A box showing the results of the marked items labeled Independent Samples T-Test
  - The results of the t-test showing the value of the t calculation under 'statistic', the degrees of freedom (df), and the probability of exceeding both positive and negative values of that t under p.
  - Group descriptives showing the mean and standard deviation for each status group level along with other statistics.
8. Make sure to either screen shot this page or write down all the information listed above.

Now that you have done the t-calculations and have all the needed information: Answer the following questions in the text box for responding to this assignment.

1. What is the mean and standard deviation for each of the two groups? Make sure to indicate them by their grouping variable level name rather than whatever may have been used in the statistical program.
2. What is the value for t and the probability associated with it?
3. What is your decision on rejecting or retaining the null hypothesis?
4. Write an APA style sentence that describes the outcome of this study and includes the proper formatting for reporting of the t-test. The textbook has examples.

That's it! Remember, you are graded on this for making an honest effort to complete it fully.