Calculating Pearson Product- Moment Correlation Coefficient

what are correlation analysis used to identify

associations between 2 variables

why is a hypothesis developed in correlational analysis’s

to identify the nature (positive or negative)of the relationship between the variables being studied

what is the first correlation measure developed and is the most commonly used

pearson product- moment correlation

a negative correlation indicates that  

higher valus of X are associated with lower values of y 

the sign of r value is indicative of

the slope of the line (regression line) that can be drawn through a standard scatterplot of 2 variables 

Research Designs that utilize the Pearson r include any

associational design 

The variables involved in the research design are

attributional

Variables used in a Pearson product- moment correlation must be

measured as continuous or at the interval or ratio level

pearson correlation assumptions

• interval or ratio level data 

• normal distribution of at least one variable 

• independence of observations pairs 

• homoscedasticity 

homoscedasticity

when data is evenly dispersed both above and below the regression line

what does homoscedasticity reflect 

equal variance of both variables 

For every value of x the distribution of y values should

have equal variability 

After establishing the statistical significance of the r what should happen next 

determine clinical importance 

what does coefficient of determination represent

the percentage of variance shared between the 2 variables

how to get the Coefficient of Determination

Take r² and multiply by 100%