COMM 2301 Lecture Notes - Lecture 3: Test Statistic, Null Hypothesis, Statistical Hypothesis Testing

• School: Northeastern University
• Department: Communication Studies
• Course: COMM 2301
• Professor: bobbivangilder

Document Summary

If two variables are logically associated, but time order and all other explanations cannot be ruled out, we have correlation: this is a mathematical expression of how two variables are related, positive (direct) correlation. Inverse (indirect) correlation: measures how strongly two variables are related, mathematical expression of the relationship, measures the amount of variability that is shared between two variables. Correlation coefficient: designated by r , correlation coefficients are always between -1 and 1, they are expressed as decimals, the closer you are to zero, the weaker the relationship. No relationship/very weak: two variables are traveling in the same direction, you will know if a correlation is positive by looking at its sign. Negative (indirect) correlation: two variables are traveling in opposite direction, again, look at the sign. Examples: determine if there is zero correlation, positive correlation, or negative correlation.