On a dot plot each dot represents one occurrence of a value on a number line. The more dots stacked above a number, the more frequently that value occurs in the data set.To determine the median value of a dot plot, first arrange the dots in ascending order based on their position on the number line. Then, count the total number of dots to determine if it is an odd or even number. For an odd number of dots, the median is the value at the middle position. For an even number of dots, the median is the average of the values of the 2 dots in the middle.