T-test report

t-test project: psy3020

Research Study Overview
The goal of this research study is determine if CBT (cognitive behavior therapy) is effective in treating with people with

depression.

Purpose
The purpose of this study is to show that 6 CBT treatments over a 12 week time period can reduce the symptoms of

depression in adults with physician diagnosed clinical depression.

For this study, researchers had a participant pool included 112 people who self-selected to be involved in a study for the

treatment of depression. No compensation was provided to participants. All measures and treatment were free to all

participants. To be considered for the study, participants must meet the inclusion criteria:

 Participants were suffering from physician diagnosed (e.g. DSM-IV, ICD-9) clinical depression.

 If participants were receiving pharmacological treatment for their depression, they had to be on

pharmacological treatment for at least 4 weeks prior to study.

 Participants had to have current episodes of depression lasting at least 6 months.

 Participants could not be currently involved in another psychological treatment.

A sample of 40 participants (22 females, and 18 males) was randomly selected from the pool for this study. The age of

the participants range from 22 – 39 years with an average of 30 years old. Participants reported current episodes of

depression lasting a mean of 17.47 months (SD ¼ 28:75).

One month prior to CBT treatment, each participant was given a measure of depression. One month after CBT

treatment, the depression measure was re-administered to all participants.

The depression measure is scaled from 1– 20 with higher scores indicating more depression. Scores from 1-7 are

considered low depression, scores from 8 – 14 are considered moderate depression, and scores 15 and above are

considered severe depression.

Descriptive Statistics

The Descriptives below give us an overview of the data. The Descriptive Statistics table displays the means, standard
deviations, and other statistics of the depression ratings before the CBT treatment (Pre) began, and after treatment
(Post). Use the descriptive statistics and the histograms to describe the pre and post results.

Descriptive Statistics

Pre Post

Valid 40 40

Mean 13.125 9.850

Median 12.500 10.000

Mode ᵃ 11.000 8.000

Std. Deviation 3.510 1.994

Minimum 8.000 6.000

Maximum 19.000 14.000

25th percentile 10.000 8.000

50th percentile 12.500 10.000

75th percentile 16.250 11.000

Descriptive Statistics

Pre Post

ᵃ More than one mode exists, only the first is reported

Distribution Plots

Pre – Depression scores prior to CBT treatment

Post – Depression scores after CBT treatment

Paired or dependent samples t-test

The table displays the results of the t-test. It contains the t -test results, the degrees of freedom, the p-value of the t-
test, and the effect size Cohen’s d. The plot shows the differences in the mean between the two time periods. Use the
results determine if the null hypothesis is true.

Paired Samples T-Test

Measure 1 Measure 2 t df p Cohen’s d

Pre – Post 6.974 39 < .001 1.103

Note. Student’s t-test.

Descriptives Plots

Pre – Post

Running head: Title

Title

Your Name

Title

Method

Participants

Procedure

Results

Discussion

Writing up results for projects in APA

You will write a method, results, and discussion section. Below is a description of what should be

included in each section

Method (labeled, centered, bold)

The Method section of an APA-style paper is the most straightforward to write, but requires precision.

Your goal is to describe the details of your study in such a way that another researcher could duplicate

your methods.

The Method section typically includes Participants and Design, Materials and/or Apparatus, and

Procedure sections.

Participants and design (labeled, flush left, bold)

Total number of participants, and any demographic information about the participants, such as gender,

age. Also, include how the participants were selected. Randomly? Were they compensated for their

time in any way? (e.g., money, extra credit points)

Materials (labeled, flush left, bold)

Carefully describe any materials or stimuli used in the study.

 If you included a questionnaire, you should describe it. For instance, note how many items were

on the questionnaire, what the response format was (e.g., a 5-point Likert-type scale ranging

from 1 (strongly disagree) to 5 (strongly agree)).

Procedure (labeled, flush left, bold)

What did participants do, and in what order?

Results (labeled, centered, bold)

The results section is the place in the report where you summarize your data and report the findings of

any relevant statistical analyses.

In APA style, the results section includes preliminary information about the participants and data,

descriptive and inferential statistics, and the results of any exploratory analyses.

Include these in your results section:

 Participant flow and recruitment period. Report the number of participants at every stage of the

study.

 Descriptive statistics. Summarize the primary and secondary outcomes of the study.

 Inferential statistics, including confidence intervals and effect sizes. Address the primary and

secondary research questions by reporting the detailed results of your main analyses.

 Write up the results in the past tense because you’re describing the outcomes of a completed

research study.

Descriptive statistics
The exact descriptive statistics that you report depends on the types of data in your study. Categorical

variables can be reported using proportions, while quantitative data can be reported using means and

standard deviations. For a large set of numbers, a table is the most effective presentation format.

Include sample sizes (overall and for each group) as well as appropriate measures of central tendency

and variability for the outcomes in your results section. For every point estimate, add a clearly labelled

measure of variability as well.

Inferential statistics
For each statistical test performed, first restate the hypothesis, then state whether your hypothesis was

supported and provide the outcomes that led you to that conclusion.

Report the following for each hypothesis test:

 the test statistic value,

 the degrees of freedom,

 the exact p-value (unless it is less than 0.001),

 the magnitude and direction of the effect.

What doesn’t belong in your results section?

It’s important to provide a complete picture of your data analyses and outcomes in a concise way. For

that reason, raw data and any interpretations of your results are not included in the results section.

Raw data: It’s rarely appropriate to include raw data in your results section.

Interpretation or discussion of results: This belongs in your discussion section. Your results section is

where you objectively report all relevant findings and leave them open for interpretation by readers.

While you should state whether the findings of statistical tests lend support to your hypotheses, refrain

from forming conclusions to your research questions in the results section.

Explanation of how statistics tests work: For the sake of concise writing, you can safely assume that

readers of your paper have professional knowledge of how statistical inferences work.

Discussion (labeled, centered, bold)

A resource for the discussion section can be found below and in the course content.

https://apastyle.apa.org/instructional-aids/discussion-phrases-guide

7th Edition

Discussion Phrases Guide

Papers usually end with a concluding section, often called the “Discussion.” The Discussion is your opportunity to
evaluate and interpret the results of your study or paper, draw inferences and conclusions from it, and communicate
its contributions to science and/or society. Use the present tense when writing the Discussion section.

• In the Discussion section of a research paper, you should evaluate and interpret the implications of study
results with respect to your original hypotheses. It is also where you can discuss your study’s importance,
present its strengths and limitations, and propose new directions for future research.

• In other types of papers, such as essays or reaction papers, the Discussion is where to summarize the key
points or themes in your paper and reflect on previous statements and their broader connections.

This guide provides possible statements to use when discussing specific types of content in the Discussion
section of a research paper. These are examples of only some, but not all, of the phrases that can be used in the
Discussion section of all APA Style papers. Check with your instructor for specific guidelines on the content to
include in your Discussion section.

Summarizing your study results
• The purpose of this study was to gain a better

understanding of …

• The results of the present study support the
hypothesis that …

• The results of this research provide supporting
evidence that …

• There are three key findings of the present
research. First … Second … Third …

Linking findings to previous research
• This pattern of results is consistent with the

previous literature … (citation).

• These results are consistent with the claim that …

• The present results are consistent with Author et
al.’s (year) work that deals with …

• Whereas past researchers have found … (citation;
citation; citation), the present study has shown …

• These results represent the first direct
demonstration of …

Discussing research results
• Our findings highlight …

• The results strongly imply that …

• It is interesting that …
• In my view, the most compelling explanation for

the present set of findings is that …

• This idea is further supported by the finding that …

• Two other results from this study merit comment.
First … Second …

• Finally, we obtained evidence that …

• One interpretation of these findings is that …

• This finding may be explained by the idea that …

• Taken together, our findings indicate …

Study limitations
• There are at least three potential limitations

concerning the results of this study. A first limitation
concerns … A second potential limitation is that …

• One limitation of this study is that … It is possible
that … Although the present research cannot rule
out these explanations, it seems useful to point out
issues that may conflict with these results.

• Although the present results clearly support …, it is
appropriate to recognize several potential
limitations.

• Besides our own interpretation of the data,
an additional explanation warrants comment. For
example, researchers have suggested … (citation).

• Certain limitations of this study could be addressed
in future research. For example …

• The present study represents a first attempt to
address these issues. We feel that further research
examining … may shed light on …

Study implications
• Despite these limitations, these results suggest

several theoretical and practical implications.

• These data have some potential intervention
implications. For example …

Directions for future research
• Although these studies support … , their most

important contribution may be that they raise a
variety of intriguing questions for future study.

• In terms of future research, it would be useful to
extend the current findings by examining …

• If, as the present study suggests, … then there is a
need for research that explores …

• Much work remains to be done before a full
understanding of the extent of … is established.

• In addition to those already mentioned, I suggest
several avenues of research that may be helpful.

Closing statement or paragraph
• Despite these limitations, this research can be

seen as a first step towards integrating two lines
of research, [x and y], that, to our knowledge, have
not been directly linked.

• Despite these limitations, the present study has
enhanced our understanding of the relationship
between [x and y]. We hope that the current
research will stimulate further investigation of this
important area.

• The present research, therefore, contributes to a
growing body of evidence suggesting that …

• In summary, our research replicates (citation) …
The findings contribute to a growing body of
evidence …

• Although the generality of the current results must
be established by future research, the present
study has provided clear support for … Not only
was … Furthermore …

More information on content to include in the Discussion section of
quantitative and qualitative research papers can be found in Sections
3.8 and 3.16 of the Publication Manual of the American Psychological
Association (7th ed.).

SOURCE: American Psychological Association. (2020).
Publication manual of the American Psychological
Association (7th ed.). https://doi.org/10.1037/0000165-000

CREDIT: TRACI GIULIANO, SOUTHWESTERN
UNIVERSITY