No, we do not agree with the statement. There are various types of diagrams. A diagram is a two-dimensional geometric figure that represents information in a visual form. Some of the statistical diagrams are as follows:
i. Bar diagrams - A simple bar diagram comprises a group of rectangular bars for each class of data. They are one-dimensional diagrams in the sense, that it is only the height of the bars that matters and not the width. The height of the bars in the diagram differs according to the values of different variables while the width of different bars remains the same.
ii. Pie diagrams - A pie diagram is a circular chart or diagram that is further dissected into parts representing different components of the given data. Each segment or part represents an item of the given data set. The area of each part (or central angle) is proportional to the quantity (or information) it represents.