"A graph, like a general table, may be prepared with no other object in view than to present in graphical form a given set of facts." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"A graph is a pictorial representation or statement of a series of values all drawn to scale. It gives a mental picture of the results of statistical examination in one case while in another it enables calculations to be made by drawing straight lines or it indicates a change in quantity together with the rate of that change. A graph then is a picture representing some happenings and so designed as to bring out all points of significance in connection with those happenings. When the curve has been plotted delineating these happenings a general inspection of it shows the essential character of the table or formula from which it was derived." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"A nomograph of a formula is a graph or diagram composed of lines scaled relatively and placed in such relative positions that the values of the variables are found on a line crossing the scales. The object is to substitute for the labor of computation a simple mechanical operation such as the one previously described. It is easy to read a nomogram with precision because of the few lines. It provides a tabulation of all possible values, enables solutions to be made irrespective of what quantity in the formula is unknown and also enables one to observe instantly the effect of a change, either small or great, in any one of the variables. The principles of such diagrams may be given in a general way and simple nomograms be constructed, but equations with many unknown quantities cannot be solved graphically without higher mathematics." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"At the present time there is a total lack of standardization in the form of diagram to use for nearly all classes of representation. This makes it difficult to compare reports of different investigators on the same subject because their diagrams are not constructed alike." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"Business executives cannot afford to ignore the merits of graphical representation which have for so long been accepted by the engineer and man of science. They must look behind the graphical method and study the conditions leading to the picture along with the picture itself. No business is too small to profit by an examination which shall analyze and scrutinize nor too large to ignore its possibilities. Each business must adjust the graphical methods to its own peculiarities and each diagram must be adjusted to the individual for whom it is prepared or the individual must be educated up to the use and importance of these methods of analysis." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"Graphical methods are employed to a large extent in physical investigations as aids to calculation and for the purpose of exhibiting the nature of the law of variation of various phenomena." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"Graphical methods are inferior to numerical in accuracy. Ease and rapidity are essential when we want to compare many sets of facts together because if the mind is long delayed in taking in the facts of one set it loses count of the others. The function of graphical representation is to facilitate comparison." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"Graphical methods comprise all those methods of representing the relations of objects or facts by means of the relations between the lines of a diagram. All devices for representing by geometrical figures the numerical data which result from the quantitative investigation of phenomena are included under this title." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"Readers of statistical diagrams should not be required to compare magnitudes in more than one dimension. Visual comparisons of areas are particularly inaccurate and should not be necessary in reading any statistical graphical diagram." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
"The chief problems in the technique of historigram [aka histogram] plotting are those of base line scales, types of lines to use for the graphs and methods of and purposes of smoothing these curves. The size of page, ability of grasp by the eye, subsequent treatment of the illustration, etc., are determining factors. The variable factor is usually plotted from a base line along the ordinate axis. Spacing and rules for scales apply as in frequency diagrams." (William C Marshall, "Graphical methods for schools, colleges, statisticians, engineers and executives", 1921)
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