Title: Mini Project 2
Course: PSYC 301 Statistical Methods in Psychol > Section: Second Part of Course

For Mini Project 2, we will be testing a hypothetical situation of adding a specific medication used in HIV treatment to the Johnson & Johnson vaccine to see if that increases its effectiveness. The effectiveness in preventing moderate and severe disease is 66%.^1 That will be our null hypothesis test value in the analysis. Our hypothetical data is in this file named Covid.omv (jamovi format, click to download for your use in your copy of jamovi).

The variable we want to test is "COVID Test". It has levels of Positive and Negative. The null hypothesis says the J&J vaccine alone provides 66% protection meaning we would expect 66% of persons to test Negative. Our scientific hypothesis says that the addition of the HIV medication should increase the effectiveness to a value above 66% (though if it deviated below 66% we would find that interesting and want to know it, hence the use of a two-tailed test).

Follow these steps:

1. Click on this link to download the jamovi (.omv) file.
2. Open that file in jamovi.
3. You'll see that you have a file with two columns
  1. ID (which is the identifier for each participant)
  2. COVID Test: The results of a COVID test done on the participant 1 month after vaccination
4. Select the Analyses tab
5. Select the Frequencies icon (5th icon over, looks like a waffle)
6. Select the first choice for One Sample Proportions Tests that is named 2 Outcomes Binomial test
7. Select COVID Test and click the arrow to move it to the right hand box.
8. Confirm the following:
  1. Values are counts is NOT checked
  2. Test value is 0.66 (change it to that if it is some other value)
  3. Hypothesis is marked for ≠ Test Value
  4. Confidence intervals is NOT checked
9. In the right hand pane of the window are the results of the Proportion Test (2 outcomes) and it tells you the following: The count and proportion for High and Low values and the probability for those proportions to be seen if the null hypothesis value of 0.66 is the basis for the distribution from which the data came. Note below the table is  the alternative hypothesis description using jamovi's terminology.
10. We are interested in the proportion of COVID Tests that are Negative. We would expect them to be 66% or more. Note if this proportion is greater than .66 or less than .66.
11. Look at the probability for the Negative level of COVID Test. If it is less than .05, then we can reject the null hypothesis that the proportion of Negative COVID Tests is similar to .66. But, if that probability is greater than 0.05, then we retain the null hypothesis.
12. More specifically, if the null hypothesis is rejected, that is telling you that the observed proportion differs enough from .66 that you are confident that the addition of HIV is making the vaccine perform better or worse (depending on which way the deviation goes, higher or lower).
13. Keep this jamovi information up on screen, screen-shot it, or write it down so you can write it up as described below.

This is where you pick up after going to one of the two pages for how to do the analysis.

You now have a probability of the data for this project having come from the null hypothesis distribution, along with the proportions of high and low values being rolled.

That means you can now write a short report using Microsoft Word (which is available via Office 365 through your browser access to your email).

Your report will have the following sections:

1. introduction and method
2. results
3. discussion

You are NOT writing an APA report because this is much simpler than that and more direct. The most important thing for you to know is this: While we talk in statistics about null and alternative hypotheses, we NEVER use those two terms in writing our reports. Never. We only speak of our research hypothesis and how the statistical test is either supportive or not supportive of our research hypothesis.

Mentioning the null or alternative hypothesis will result in lost points.

In the introduction and method you are describing IN YOUR OWN WORDS the basic issue being examined and the meaning of the variables and levels of the variables.

In the results we are describing the basic finding of the statistical test. It will include the proportions of high and low outcomes and the outcome of the binomial test which is  the probability that was found. For example:

When reporting test results, we always report some descriptive statistics as well. In this case, a frequency table will do. Regarding the significance test, we'll write something like “A binomial test indicated that the proportion of female spiders of .47 was lower than the expected .75, p = .017 (2-sided)”. (modified example from https://www.spss-tutorials.com/spss-binomial-test/)

The above example is a report of a statistically significant finding (the p was less than .05). If you are reporting a non-significant finding it would read like this, "... of female spiders of .47 was not lower than the expected .75, p = .184..."

Because there are very few ways to write the results of a statistical test, plagiarism in phrasing is not considered an issue there, generally. But, please, we are looking at Positive and negative COVID Tests, not spiders. (Yes, I've had students write that they tested spiders... I've had them cut and paste the above sentence about spiders...)

In the discussion write about what the statistical test means in the context of the research hypothesis.

Each of these sections is going to be about two to five sentences long. This is a very short document.

Submit it using the submission method of this assignment as a Word document.

1) Note: The effectiveness values are approximations from news reports for simplicity for this exercise. No such test of adding a medication has been done as far as I am aware, therefore, this is all hypothetical to create an example for classroom work.