PY 355 Lecture Notes - Lecture 9: Pearson Product-Moment Correlation Coefficient, Hypochondriasis, Scatter Plot

• School: University of Alabama
• Department: Psychology
• Course: PY 355
• Professor: Craig Walter Cummings

Document Summary

Correlational research correlational research: describes the relationship between two or more naturally occurring variables. Variables can be either positively or negatively related. Positive correlation: a direct, positive relationship between two variables; as one variable increases, the other variable increases. Negative correlation: an inverse, negative relationship between two variables; as one variable increases, the other variable decreases the magnitude or numerical value of a correlation expresses the strength of the relationship between the two variables. When r = . 00, the variables are not related. A correlation of . 78 indicates that the variables are more strongly related than does a correlation of . 30. Magnitude is unrelated to the sign of r; two variables with a correlation of . 78 are just as strongly related as two variables with a correlation of -. 78. Graphic representation of correlations: scatter plot: a g(cid:396)aph of pa(cid:396)ti(cid:272)ipa(cid:374)ts" s(cid:272)o(cid:396)es o(cid:374) t(cid:449)o (cid:448)a(cid:396)ia(cid:271)les, when there is a perfect correlation all of the data will fall in a straight line.