a dot plot is when you plot data points
if you know what a graph (like x and y) is, then it is like that
you put data (usually taking data of 2 different things, like time and height) on the graph with one axis being for 1 item and the other axis for the other item
if you were to graph money spent to number of burgers bought, (assuming the cost of a burger was the same every time), then you would get a linear plot that shows a correlation (connection or relationship) between the 2 items
a dot plot can help you visualize trends between 2 or more items and make judgements or guesses based on the data available