Correlational & Differential Designs &

APA Results

Psychology 291

November 4 – 6, 2013

Correlational Design

• Research that seeks to measure the relationship between variables.

• Has multiple continuous variables.

2. How much fun do you expect to have on Halloween?

3. How many alcoholic beverages do you plan on consuming Halloween night? ( 1 alcoholic beverage = 12 ounces of Beer, 4 ounces of wine, 1 ounce of hard liquor) _________

1 2 3 4 5 6 7No Fun Indifferent Lots of

Fun

Differential Design

• Research that involves comparing two or more existing groups on some variable.

• Nominal and continuous variables.

1. Are you going to dress up in a costume for Halloween?Yes or No

2. How much fun do you expect to have Halloween night?1 2 3 4 5 6 7

No Fun Indifferent Lots of Fun

APA FormatResults

APA Rules to Keep in Mind• Write in Past Tense

• First-level headings are centered and bold

• Remember to follow other APA rules (page layout, font, etc.), as well as consult the manual on-line

• Check APA format for Number formatting– All numbers zero through nine are written in word form unless they are followed by a unit of

measure– All decimal numbers and numbers greater than 10 are written in Arabic numerals– Any number that begins a sentence must be in written form– Back to back numbers are written in word and number form: Twenty 20 inch monitors

Results• Results section is “all about the data”

– All data and results (even those that run counter to hypotheses) must be reported here

• Summarizes data collected and stats that were run

• Should begin with a description of the statistical test that was used

• May direct reader to Tables and/or Figures

• Do not interpret or discuss the results

Types of Results

• Descriptive Statistics – Means, Standard Deviations, Ranges…

– Tables & Figures

• Inferential Statistics– Results of Statistical Analysis

– e.g. ANOVA, t Test, Correlation, Chi Square …

Reporting Central Tendency & Dispersion

• Measures of Central Tendency and Dispersion (e.g. means and standard deviations) are often given in the Results section

• If you are reporting a mean, it should always be accompanied by a measure of dispersion

• Often presented in Tables to simplify presentation and when there are too many values to reasonably relay (See Table 1)

• Example in text: – The mean score for men on the verbal test was 23.6, with a standard deviation

of 2.10.

•  Example following text: – Women (M = 26.94, SD = 1.98) had a slightly higher score than men (M =

23.61, SD = 2.10) on the verbal.

Inferential Statistics• The type of statistical test that you will choose

depends on:

– The type of data collected • Nominal, ordinal, interval, ratio

– The type of research design• Experimental

• Differential (quasi-experimental)

• Correlational

Reporting Inferential Statistics

t (81) = 2.598, p < 0.05

•The letter of the test (t, F, r, etc. and p) and M and SD all need to be italicized but not the numbers or symbols (=, <, etc.)

•Statistics must be part of a sentence

Type of Test

Degrees of Freedom

Obtained Valued

P value tells you if the test is significant or not

What is this “p” value thing?

• Every decision we make as the potential to be the wrong one (i.e. due to chance rather than our manipulation)

• The p value is our “acceptable risk”

• If we set α = .05 we accept a 1 in 20 chance of making the wrong decision, therefore:

If the p value is less than (<) 0.05 the test is significant

If the p value is more than (>) 0.05 the test is not significant

Experimental Design

A One-Way ANOVA was performed and significant differences were found between at least two groups, F(2,44) = 3.835, p < .05. Tukey’s post hoc test revealed that participants in the Alcoholic Beverage Condition (M= 63.75, SD= 7.19) and the Non-Alcoholic Beverage Condition (M= 53.13, SD= 7.93) had significantly longer reaction times (in ms) than participants in the Water condition (M= 39.33, SD= 16.68).

ANOVA

ReactionTime

  Sum of Squares df Mean Square F Sig.

Between Groups 41.363 2 20.682 3.835 .029

Within Groups 237.275 44 5.393    

Total 278.638 46      

Differential Design

An Independent Samples t-test was performed and participants who were going to wear a Halloween costume (M= 6.02, SD= 1.02) anticipated having significantly more fun than participants who reported that they were not going to wear a Halloween costume (M= 4.40, SD= 1.30), t(74) = -5.185, p < .05.

Correlational Design

A Pearson correlation revealed a significant positive correlation between the amount of fun anticipated and number of alcoholic beverages participants intended to consume, r(74) = .466, p < .05. As number of alcoholic beverages consumed increased, so did the amount of fun anticipated and vice versa.

Tables and Figures• Tables and Figures may be used to clarify data being

presented in a Results section however they should never appear in the body of your text– Tables are often used to report means and standard

deviations

– Figures are used to represent interactions between variables and emphasize differences between groups

• Direct readers by adding (Table 1) or (Figure 1) at the end of sentences in your Results section

• They should not repeat information presented in the Results section

Tables

• Tables are used to present data when it would be unmanageable to present them in the results section (i.e. too many M & SD)

• Are presented in the a sans serif font (e.g. Arial) size 12

• Contain no vertical lines

• Contain minimal horizontal lines

• Begin with a Table number and description

• Follow after References and Appendices

SAMPLE APA PAPER 13

Table 1Mean response time of participants (ms) after consuming different beverages.

Condition M (SD)

Alcoholic Beverage 63.75 (7.19)

Non-alcoholic Beverage 53.13 (7.93)

Water 39.33 (16.68)

Figures• Greyscale (no colours)

• Label Axes but do not include a title

• Legends (if applicable) must fall within the axis lines

• Figure presented in a sans serif font (e.g. Arial) between size 8 - 14

• Figure Caption presented in serif font (same as body of text) size 12– Goes below the figure and describes the what is being shown

• No gridlines or borders (the only lines will be the axes)

• Follow after References, Appendices, and Tables

• Figure should fill the width of the page

• If presenting means, SD or SEM should be included as error bars

SAMPLE APA PAPER 14

Figure 1.A comparison of the amount of fun anticipated by participants either wearing or not wearing a costume on Halloween. (Error bars represent +/- SEM)

*

APA FormatDiscussion

APA Rules to Keep in Mind

• Past Tense

• First-level headings are centered and bold• “Method”; “Results”, “Discussion”

• Remember to follow other APA rules (page layout, font, etc.), as well as consult the manual on-line

General Discussion Info

• In this section, the goal is to discuss and evaluate your results, and whether or not the results support your hypotheses.

• Relate your findings to literature from Intro.– You may not introduce new sources; use only

sources from your Intro

• Start Specific and end General

Discussion must include:• A clear statement of support or non-support

for your original hypotheses

– Note: You do not prove your hypotheses; you support or fail to support them

• Similarities and differences between your results and those of previous research– Relate to research from Introduction

Implications

• Implication (noun): the conclusion that can be drawn from something although it is not explicitly stated

• Evaluate and interpret the implications of the results with respect to your hypotheses

• Include a discussion of the theoretical, clinical or practical implications of your results

Implication. (2005).  In Oxford Reference Online. Retrieved from http://www.oxfordreference.com/views/ENTRY.html?subview=Main&entry=t140.e37617

Limitations• Limitation (noun): a limiting rule or circumstance; a

restriction; a condition of limited ability; a defect or failing

• Highlight the shortcomings of your study

• Suggest explanations to account for hypotheses that were not supported – Methodological (examine methodology critically)– Conceptual

• Sources of error or bias that may have affected the results

Limitation. (2005). In Oxford Reference Online. Retrieved from http://www.oxfordreference.com/views/ENTRY.html?subview=Main&entry=t140.e44028

Future Research

• Suggestions for future research should always be made

• Indicate future directions this research could take

• Indicate improvements to methodology that may benefit future attempts to replicate

• What problems remain unresolved or were raised as a result of your research?

How to critically appraise an Article

1. Is the study question relevant?

2. Does the study add anything new?

3. What type of research question is being asked?

4. Was the study design appropriate for the research question?

5. Did the study methods address the most important potential source of bias?

6. Was the study performed according to the original protocol?

7. Does the study test a stated hypothesis?

8. Were the statistical analyses performed correctly?

9. Do the data justify the conclusions?

10. Are there any conflicts of interest?

(Young & Solomon, 2009, pp.83)