Running and Interpreting Correlation
Tests
Justin D’Souza
Quantitative Specialist
Table of
Contents
Statistics Solutions Services
Correlation Tests
Intellectus Demo
Summary
Need help with your dissertation? Call 727-442-4290
Services Offered
by Statistics
Solutions
• Topic Development
• Prospectus or Concept Papers
• Introduction Chapter
• Literature Review Chapter (identifying articles)
• Methodology Chapter (Quantitative/Qualitative).
• IRB forms
• Data entry templates
• Survey Monkey upload
• Results Chapter (Quantitative/Qualitative)
• Discussion Chapter
• Powerpoints for Defense
• Journal Publications
 Need help with your dissertation? Call 727-442-4290
Parametric and
Non-Parametric
Statistics
Parametric Techniques
 Parametric statistics are based on assumptions about the distribution of population from
which the sample was taken.
 Usually this “assumption” is that the data follows a normal (bell-shaped) distribution.
 Parametric techniques usually involve examining a continuous variable.
Non-Parametric Techniques
 Nonparametric statistics are not based on assumptions, that is, the data can be collected
from a sample that does not follow a specific distribution.
 A normal (bell-shaped) distribution is not required for non-parametric techniques.
 Non-parametric techniques usually involve examining nominal or ordinal variables.
Need help with your dissertation? Call 727-442-4290
Relationship
between two
numerical
variables
Parametric Technique
 Pearson Correlation– Appropriate statistical analysis when testing for relationship between
two continuous-level variables.
 Example: Is there a significant relationship between mileage and horsepower?
Non-Parametric Technique
 Spearman’s Rho and Kendall’s Tau Correlation– Appropriate statistical analysis when
testing for relationship between two variables, when at least one of the variables is
measured ordinally.
 Example: Is there a significant relationship between mileage categories and
horsepower?
Need help with your dissertation? Call 727-442-4290
Relationship
between
continuous and
dichotomous
variable
Parametric Technique
 Point-biserial Correlation– Appropriate statistical analysis when testing for
relationship between dichotomous and continuous-level variables.
 Example: Is there a significant relationship between transmission type of a
car (automatic vs manual) and mileage?
Non-Parametric Technique
 If you have a dichotomous variable and an ordinal variable, there is not a non-
parametric equivalent to the point-biserial correlation. Instead the approach will
need to be shifted to a Mann-Whitney U test to test for differences in ordinal
variable by dichotomous variable.
Need help with your dissertation? Call 727-442-4290
Relationship
between two
nominal-level
variables
Non-Parametric Technique
 If you have are testing the relationship between two nominal-level variables, run
a chi-square test of independence
 Example: Is there a significant relationship between transmission type and
engine type?
Need help with your dissertation? Call 727-442-4290
Summary
 Determine what level of measurement of variables you are using. .
 Determine if data follow a normal distribution.
 Pinpoint analysis to address research questions.
 Use Intellectus Statistics to analyze your data and present interpretation.
Need help with your dissertation? Call 727-442-4290
Additional
Support
Statistics Solutions is a full-service dissertation consulting
company providing graduate students timely, editorial
support for their dissertations and scholarly projects
For information about our services, receive a
complementary 30-min consultation available Mon-Fri 9-5
ET
Contact us at info@statisticssolutions.com
Phone: 727-442-4290

Running and Interpreting Correlation Tests

  • 1.
    Running and InterpretingCorrelation Tests Justin D’Souza Quantitative Specialist
  • 2.
    Table of Contents Statistics SolutionsServices Correlation Tests Intellectus Demo Summary Need help with your dissertation? Call 727-442-4290
  • 3.
    Services Offered by Statistics Solutions •Topic Development • Prospectus or Concept Papers • Introduction Chapter • Literature Review Chapter (identifying articles) • Methodology Chapter (Quantitative/Qualitative). • IRB forms • Data entry templates • Survey Monkey upload • Results Chapter (Quantitative/Qualitative) • Discussion Chapter • Powerpoints for Defense • Journal Publications  Need help with your dissertation? Call 727-442-4290
  • 4.
    Parametric and Non-Parametric Statistics Parametric Techniques Parametric statistics are based on assumptions about the distribution of population from which the sample was taken.  Usually this “assumption” is that the data follows a normal (bell-shaped) distribution.  Parametric techniques usually involve examining a continuous variable. Non-Parametric Techniques  Nonparametric statistics are not based on assumptions, that is, the data can be collected from a sample that does not follow a specific distribution.  A normal (bell-shaped) distribution is not required for non-parametric techniques.  Non-parametric techniques usually involve examining nominal or ordinal variables. Need help with your dissertation? Call 727-442-4290
  • 5.
    Relationship between two numerical variables Parametric Technique Pearson Correlation– Appropriate statistical analysis when testing for relationship between two continuous-level variables.  Example: Is there a significant relationship between mileage and horsepower? Non-Parametric Technique  Spearman’s Rho and Kendall’s Tau Correlation– Appropriate statistical analysis when testing for relationship between two variables, when at least one of the variables is measured ordinally.  Example: Is there a significant relationship between mileage categories and horsepower? Need help with your dissertation? Call 727-442-4290
  • 6.
    Relationship between continuous and dichotomous variable Parametric Technique Point-biserial Correlation– Appropriate statistical analysis when testing for relationship between dichotomous and continuous-level variables.  Example: Is there a significant relationship between transmission type of a car (automatic vs manual) and mileage? Non-Parametric Technique  If you have a dichotomous variable and an ordinal variable, there is not a non- parametric equivalent to the point-biserial correlation. Instead the approach will need to be shifted to a Mann-Whitney U test to test for differences in ordinal variable by dichotomous variable. Need help with your dissertation? Call 727-442-4290
  • 7.
    Relationship between two nominal-level variables Non-Parametric Technique If you have are testing the relationship between two nominal-level variables, run a chi-square test of independence  Example: Is there a significant relationship between transmission type and engine type? Need help with your dissertation? Call 727-442-4290
  • 8.
    Summary  Determine whatlevel of measurement of variables you are using. .  Determine if data follow a normal distribution.  Pinpoint analysis to address research questions.  Use Intellectus Statistics to analyze your data and present interpretation. Need help with your dissertation? Call 727-442-4290
  • 9.
    Additional Support Statistics Solutions isa full-service dissertation consulting company providing graduate students timely, editorial support for their dissertations and scholarly projects For information about our services, receive a complementary 30-min consultation available Mon-Fri 9-5 ET Contact us at info@statisticssolutions.com Phone: 727-442-4290