Problem 2: Expressive writing and physical health

A team of researchers is interested in the effect on physical health of writing about thoughts and feelings associated with traumatic life events (Expressive Writing). The researchers recruit 32 undergraduate students to take part in the study and randomly assign them to be in an expressive Writing Croup or a Control Group. Students in the expressive writing group are instructed to write four 20 - minute essays over four consecutive days about their most traumatic life experiences. Students in the control group write four 20 - minute essays over consecutive days describing their plans for that day. One week later, the researchers ask the students to rate their overall level of physical health (on a scale 0 = very poor health to 100 = perfect health).

EWG: 75, 86, 77, 91, 68, 74, 62, 93, 82, 79, 94, 56, 79, 86, 90, 97

CWG: 81, 76, 71, 70, 62, 50, 58, 63, 76, 64, 65, 72, 52, 59, 60, 61

The researchers were interested in identifying a positive or a negative health effect of expressive writing. Run the proper t testto see if this previous research is supported.

Independent variable: ______________________________________________________

Dependent variable: _______________________________________________________

Statistical Hypotheses: H₀: ___________________ H₁: ______________________

State Hypotheses in words:

H₀: __________________________________________________________________________

H₁: __________________________________________________________________________

Proper t-test: ___________________ One-tailed or two-tailed? _ _______________

Run the analysis using JASP and "print" and INCLUDE the t-test output. Include a boxplot of both groups in your write-up. Using APA style, report your conclusions in the words (using the variables) of this study based on the research hypothesis and the statistical results.

Was the data normally distributed? Were the variances of the two groups significantly different from each other? What does that mean?