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Grab barchart information and draw sector statistical maps

Shandong yu sukun

Barcharts and sector charts are different types of statistical charts, each of which has advantages and disadvantages. In practical matters, it is often necessary to draw sector charts based on information from barcharts.

Example 1 shows, as figure 4, the number of students in the ninth grade of a secondary school using a bar chart of the number of different brand calculators to try out the following questions:

(1) what brand calculators do you think are used most frequently? And get out of this frequency; (2) use a fan statistical chart to indicate the data in the histogram of frequency distribution; and (3) use the above statistical results to suggest a rationalization for commercial purchases.

Figure 1 figure 2

Analysis: according to the bar statistical chart, the students surveyed used the acculator 36 people, the b calculator 54 people and the c calculator 90 people, which allows the calculation of the total population and thus the percentage of total a, b and c survey population to be calculated, the corresponding circular angles are calculated and a sector statistical chart is drawn.

Solve: (1) c calculator with maximum frequency of 36+54+90 = 180 (person)

X 100% = 50%. The frequency of the calculator is 50%.

(2) a: 100 per cent = 20 per cent and a circular angle of 360° = 20 per cent = 72°

B: 100 per cent = 30 per cent, with a circular angle of 360° x 30 per cent = 108°

C: x 100% = 50%, with a circular angle of 360° x 50% = 180°.

The statistics are shown in figure 2.

Steps for drawing sectoral statistical maps

(3) when merchants are advised to enter, the deck, card b, card c calculator is required to do so at 2:35, thereby reducing stocks.

[commentary] the subject of such tests is an important one in the examination, and care should be taken to understand the methodology and the steps.

Case 2 as shown in figure 3 is a bar chart based on the age of students in class 9 (3) at a secondary school.

(1) based on the information provided in the diagram, a sectoral statistical chart is drawn showing the distribution of students in the class;

Compare the two statistical charts and tell us what their respective strengths and weaknesses are.

Figure 3

Analysis: the key to the production of sector statistical maps is to obtain correct data from strip statistical charts: 4 people aged 13, 15 people aged 14, 25 people aged 15 and 6 people aged 16, for a total of 50 people. On the basis of these data, the necessary calculations can be made to produce sector statistics.

E: (1) calculation of the percentage of the population of different ages as a percentage of the total class and the degree of the contours of the corresponding sector:

Steps for drawing sectoral statistical maps

13 years: 4 x 50 per cent = 8 per cent, 360 x 8 per cent = 28. 8°; also calculated at 30 per cent for 14 years and 108° for the contours; 50 per cent for 15 years and 180° for the contours; 12 per cent for 16 years and 43. 2° for the contours. The figures are shown in figure 4.

(2) the advantage of the schematic statistical chart is that it provides a visual reflection of the percentage of the total number of persons of each age as a percentage of the total number of persons in the class, and that it is insufficient to see the exact number of persons per age; a bar chart has the advantage of providing a visual picture of the exact number of persons per age, and insufficient to see the percentage of the total number of persons per age.

[commentary] sector charts and bar charts are basic statistical charts, which can be drawn on the basis of information from bar charts and, of course, sometimes on the basis of fans.