The best graphical representation for the given data would be a histogram. A histogram is a graph that displays the distribution of continuous numerical data. It consists of a series of bars, where each bar represents a range of values and the height of the bar represents the frequency or proportion of data points that fall within that range. Since the variable of interest in this case is the number of hours slept per night, which is a continuous numerical variable, a histogram would be an appropriate way to display the distribution of the data. A stem-and-leaf plot is another way to display numerical data, but it is better suited for smaller data sets. Circle graphs and bar graphs are used to display categorical data.