Homework 5 focuses on the application of concepts addressed in Exercises 16 and 31. Homework 5 is due SUNDAY at 11:59pm.
A randomized experimental study examined the impact of the discontinuation of proton pump inhibitors (PPIs) on gastrointestinal symptoms among those with gastroesophageal reflux disease (GERD; Hendricks et al., 2021). The researchers followed two randomized groups of participants over time: those who underwent abrupt PPI discontinuation and those who underwent tapered PPI discontinuation.
A simulated subset was selected for this example so that the computations would be small and manageable. The independent variable in this example is the type of PPI discontinuation (abrupt group versus tapered group). The dependent variable was the score on the Dyspepsia Symptom Severity Index (DSSI) assessed at a follow-up assessment 14 weeks post-discontinuation. The items on the DSSI are rated on a 5-point Likert scale ranging from 0 (absent) to 4 (very severe). The null hypothesis is: “There is no difference between the abrupt and tapered discontinuation groups on the severity of dyspepsia symptoms among persons with GERD.”
A subset of simulated data from this study are presented in HW5.sav.
Download the file:
HW5.sav Download HW5.sav
Open in SPSS. Use the dataset to answer the following questions.
1.Compute an independent samples t-test using “Group” as the independent variable and “DSSI Scores” as the dependent variable. List the numerator value. Hint: No hand calculations are required for Q1 and 2. The values are found in the output.
2.List the denominator value.
3.Compute the t-test from above using SPSS. Paste the table containing the t value into your homework.
4. Is the t significant at a=0.05? Specify how you arrived at your answer.
5. What is the exact likelihood of obtaining the calculated t value at least as extreme or as close to the one that was actually observed, assuming that the null hypothesis is true? (Hint: this question is asking you for the exact p value, converted to a percentage.)
6. Write your interpretation of the results of the independent samples t-test, as you would in an APA-formatted journal.
See this file for a mean symbol to copy and paste into your homework to report means: Mean Symbol
Or this video:How to write x-bar in WordLinks to an external site.
Help for Homework 5:
Q4: There are two ways to answer this question: either compare the obtained t to the tabled t (specify the tabled t value in Appendix A), or compare the obtained p to an alpha of .05 (specify the obtained p value). Just like what is explained in Exercise 31 and in Dr. Cipher’s video ‘What is a p value‘ in Module 2.
You may submit a draft of Question 6 to Dr. Cipher for feedback (send the interpretation and only the interpretation in the body of your email).
Q6: The interpretation should be reported exactly like the APA-formatted example on page 388 in Exercise 31. Need to include the t, df, and two-sided p value.
