To find the slope of the line containing the pair of points, subtract y2 to y1 and divide x2-x1.
y2-y1
--------
x2-x1
It is false that for visualizing the relationship between a numerical and a categorical variable, a mosaic
plot is useful. This is because the best plot to use for this kind of
relationship is the side by side box plot.
Comparing the
distribution of a numerical variable across the levels of a categorical
variable is something we usually consider in this type of relationship.
The levels of one categorical variable by means of a quantitative
variable is best compared by using the visual display called the side by side
boxplot. <span>By placing single boxplots adjacent to one
another on a single scale, the side by side box plot is constructed.</span>
Since there are no negative values for x, the range starts when y=4 at x=0. This extends infinitely in the positive direction. Therefore, the range of the function is from 4 to positive infinity. In interval notation, that is [4,∞).
