A Scatterplot A $Y$ And $X$ Are Related When Their Relationship Is Scattered All Over the When

Short Answer

A scatterplot a. shows how $Y$ and $X$ are related when their relationship is scattered all over the place.
b. relates the covariance of $X$ and $Y$ to the correlation coefficient.
c. is a plot of $n$ observations on $X _ { i }$ and $Y _ { i }$ , where each observation is represented by the point $\left( X _ { i } , Y _ { i } \right)$ .
d. shows $n$ observations of $Y$ over time.