The Histogram plot has two mode in which it can appear: curve and block. When the Histogram plot is drawn as a curve, it looks like the Curve plot. When the Histogram plot is drawn in block mode, it is drawn as a bar graph where each bin is plotted along the X-axis and the height of each bar corresponds to the number of values that were assigned to that bin. You can set change the Histogram plot's appearance by clicking the Curve or Block radio buttons.