Normal Data Distribution and Two-Variable Correlation Testing
Normal Data Distribution and Two-Variable Correlation Testing Overview One of the most important steps along the researcher’s path to data analysis is to become familiar with the character of the raw data collected for the project. Before weaving the strands of data into an analytical story that is related to a study’s goals, researchers typically inspect the completeness and quality of the data with various visualization techniques (graphics), summary tables, and mathematical tests of quality (assumption tests). One of these latter tests is a correlation analysis. With this approach, the researcher performs a very basic series of exploratory tests on variable pairs to identify any potentially interesting (yet unknown) relationships between groups of data (variables). Correlational analyses are often later performed as part of the predetermined data analysis plan to answer a specific research question. Demonstration of Proficiency By successfully completing this assessment you will address the following Scoring Guide Criteria, which align to the indicated course competencies. Competency 1: Describe underlying concepts and reasoning related to the collection and evaluation of quantitative data in health care research. Interpret the overall clinical meaning and limitations of the relationship of two variables, based on a correlation analysis and literature regarding age and stress. Competency 2: Apply appropriate statistical methods using common software tools in the collection and evaluation of health care data. Create a histogram and scatter plot for variables tested for normal distribution. Perform a normal distribution assumption test for two variables to determine if data is normally distributed. Perform an appropriate correlation test to determine the direction and strength or magnitude of the relationship between two variables. Competency 3: Interpret the results and practical significance of statistical health care data analyses. Interpret the effect size for correlation analysis results. Competency 5: Address assignment purpose in a well-organized text, incorporating appropriate evidence and tone in grammatically sound sentences. Write clearly, accurately, and professionally. Cite sources appropriately, using APA formatting. Instructions For this three-part assignment, complete the following, referring to the helpful links in Resources: Part 1: Graphic Representation of the Data From the Yoga Stress (PSS) Study Data Set Using the readings, media, and resources discussed to date, create a histogram or bar graph (according to the measurement level of the data) of the following variables: Age, Education, Pre-intervention Psychological Stress Score (PSS). Using the readings, media, and other resources discussed to date, create a scatter plot of the following pair of variables: Age Versus Pre-intervention Psychological Stress Score (PSS). Part 2: Statistical Tests Perform a pre-analysis assumption test for a normal-distribution test to determine if the data you intend to use for the correlation tests passes the assumption of being normally distributed. You will use this test for Age and Pre-intervention Psychological Stress Score (PSS). Perform the appropriate correlation test to determine the direction and strength or magnitude of the relationship between these two variables from Step 1. Remember, we are not concerned about causation at this point and want to determine only if there is a statistical association. Part 3: Yoga Stress (PSS) Study Paper Include the histogram and scatter plot graphics you created earlier for Age and Pre-intervention Psychological Stress Score (PSS). Provide an interpretation for these graphics. Report the statistical outcome of the correlation analysis using appropriate scholarly style, including a brief interpretation of the effect size of the correlation.