# frequency polygon graph class 9

In earlier classes, you have already studied and constructed bar graphs. Frequency polygons are analogous to line graphs, and just as line graphs make continuous data visually easy to interpret, so too do frequency polygons. The frequency table gives information about the times it took some office workers to get to the office one day. The Corbettmaths Practice Questions on Frequency polygons. For example, it shows a greater frequency in the interval 70 - 100, than in 60 - 70, which is not the case. RS Aggarwal Class 9 Maths Solutions Chapter 17: Bar Graph, Histogram and Frequency Polygon is your ultimate practice book. So when c. Cumulative frequency graph. Let us join the mid-points of the upper sides of the adjacent rectangles of this histogram by means of line segments. Start New Online Practice Session. 14.5.1. Note : Frequency polygons can also be drawn independently without drawing histograms. (ii) We represent the number of students (frequency) on the vertical axis on a suitable scale. Do online practice, take tests, and print unlimited customized worksheets. We represent class limits along x-axis and number of students along y-axis on a suitable Scale. To create a frequency polygon, start just as for histograms, by choosing a class interval. The frequency chart below shows the results of the table. Videos, worksheets, 5-a-day and much more There is yet another visual way of representing quantitative data and its frequencies. We hope the given RBSE Solutions for Class 9 Maths Chapter 15 Statistics Ex 15.3 will help you. 14.5.2. Frequency polygons are analogous to line graphs, and just as line graphs make continuous data visually easy to interpret, so too do frequency polygons. The representation then becomes easier to understand than the actual data. Let us call these mid-points B, C, D, E, F and G. When joined by line segments, we obtain the figure BCDEFG (see Fig. The values of the variable are shown on the other axis (say, the y-axis) and the heights of the bars depend on the values of the variable. Solution : Note that the variable here is the ‘month of birth’, and the value of the variable is the ‘Number of students born’. direction and find the mid-point of the imaginary class-interval (–10) - 0. 14.8). Start New Online test. Therefore, the modified tables are: We plot the ordered pairs (5, 3), (15, 9), (25, 17), (35, 12) and (45, 9) and join the points by line segments and obtain the frequency polygon of section A. Why On the other hand, frequency polygon is an approximate curve, but still it is more usefui as compared to histogram. No, the graph is giving us a misleading picture. ABCDEFGH is the frequency polygon corresponding to the data shown in Fig. RS Aggarwal And Veena Aggarwal Class 9 Math Seventeenth Chapter Bar Graph Histogram and Frequency Polygon Exercise 17A Solution: Chapter 18 Solution. So, the resultant frequency polygon will be ABCDEFGH (see Fig. a. To construct a frequency polygon, first examine the data and decide on the number of intervals, or class intervals, to use on the x-axis and y-axis. Here, in fact, areas of the rectangles erected are proportional to the corresponding frequencies. (b) Without using Histogram: Steps: Find the class-mark (mid-value) of each given class-interval. Histogram 14.5. Chapter 19 Solution. Frequency polygons can also be drawn independently without drawing histograms. The exercise contains a total of 9 questions. Fig2: Cumulative Frequency polygon of the marks obtained by 50 students in the pre-test examination. A teacher wanted to analyse the performance of two sections of students in a mathematics test of 100 marks. Also, since       the  first class interval is starting from 30.5 and not zero, we show it on the graph by marking a kink or a break on the axis. . To find the class-mark of a class interval, we find the sum of the upper limit and lower limit of a class and divide it by 2. So, the new table obtained is as shown in the following table: We can now draw a frequency polygon by plotting the class-marks along the horizontal axis, the frequencies along the vertical-axis, and then plotting and joining the points B(145, 5), C(155, 10), D(165, 20), E(175, 9), F(185, 6) and G(195, 2) by line segments. In a school marks obtained by 80 students are given in the table. So for instance, if I have a class â10 â 19", then the midpoint is ( 10+19)/2 = 14.5. Although, there exists no class preceding the lowest class and no class succeeding the highest class, addition of the two class intervals with zero frequency enables us to make the area of the frequency polygon the same as the area of the histogram. (A) Bar graphs Frequency polygons are analogous to line graphs, and just as line graphs make continuous data visually easy to interpret, so too do frequency polygons. Recall that a bar graph is a pictorial representation of data in which usually bars of uniform width are drawn with equal spacing between them on one axis (say, the x-axis), depicting the variable. Frequency polygons are analogous to line graphs, and just as line graphs make continuous data visually easy to interpret, so too do frequency polygons. (i) The frequency polygon for a grouped data is drawn by first drawing its histogram and then by joining the mid-points of the top of bars and the mid-points of the classes preceding and succeeding the lowest and highest class respectively. To ensure that our graph is closed shape, you must determine the first and last class with zero frequencies. Represent Rational Numbers on the Number Line, Find Rational Numbers Between Given Rational Numbers, Without Actual Division Identify Terminating Decimals, Express Rational Numbers as Terminating and Recurring Decimals, Express Terminating Decimals as Fractions, Represent Irrational Numbers on the Number Line, Find Irrational Numbers Between Given Rational Numbers, Multiplication and Division of Real Numbers, Real Numbers: Mixed Operations (Simplification), Simplify and Find Values of Expressions using Rationalization, Simplify Expressions Using the Laws of Radicals, Factorization by Taking out the Common Factor, Factorization Using the Identity for Square of a Trinomial, Factorization of Sum or Difference of Cubes, Evaluate Polynomials Using Algebraic Identities, Understand the Terms Related to Coordinate Geometry, Identify the Coordinates of a Point on the Cartesian Plane, Identify the Coordinates of the Points on the X-axis, Y-axis, and the Origin, Higher Order Thinking Skills (HOTS) Related to the Cartesian Plane, Verify a Solution to a Linear Equation in Two Variables, Find the Unknown Variable When the Equation of the Line and Several Conditions are Given, Draw Graph of Linear Equations and Find the Unknown Variable, Draw Graph of Some Special Type of Linear Equations, Understanding Points, Line Segments, Rays, Lines, and Planes, Parallel, Concurrent and Intersecting Lines, Understand the Concept of Angles and Terms Related to Angles, Categorize Angles on the Basis of Their Measures, Complementary and Supplementary Pairs of Angles, Adjacent Angles, Vertically Opposite Angles, and Linear Pair of Angles, Parallel Lines, Transversal, and Angles Formed, Classification of Triangles on the Basis of its Sides and Angles, Theorems and Problems Related to Side and Angle Measures of Triangles, Problems Related to Congruence of Triangles, Understand the Concept of Quadrilaterals and Related Terms, Theorems and Problems Related to the Angles of a Quadrilateral, Theorems and Problems Related to Parallelograms, Intercept Theorem (Thales Theorem, or Basic Proportionality Theorem) and Related Problems, Theorems and Problems Related to Chord Properties of Circles, Theorems and Problems Related to Angles Subtended by Arcs/Chords, Theorems and Problems Related to Cyclic Quadrilaterals, Problems Related to Circumcircles and In-circles, Volume and Surface Area of Cuboids and Cubes, Volume and Surface Area of Circular Cones, Volume and Surface Area of Spheres, Hemispheres and Spherical Shells, Mixed Problems on Volume and Surface Area, Frequency Distribution of an Ungrouped Data, Cumulative Frequency Table of an Ungrouped Data, Histogram When the Frequency Distribution is Exclusive, Histogram When the Frequency Distribution is Inclusive, Histogram When the Class Intervals are of Unequal Size, Frequency Polygons when the Frequency Distribution is Exclusive, Frequency Polygons when the Frequency Distribution is Inclusive, Histograms and Frequency Polygons on a Single Graph, Calculate Probability for Events in Random Experiments, Area of a Quadrilateral Using Heron's Formula, Application of Results on Area of Polygonal Regions. 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