Mathematics Lab Activity-17 Class IX | Statistics

 Lab Activity-17 Class iX

Mathematics Lab Activities on Statistics for class IX students, with complete observation tables, strictly according to the CBSE syllabus.

Chapter - 11  statistics

Activity - 17

Objective: 

To draw histograms for classes of equal widths and varying widths.

Material Required:

Graph paper, geometry box, sketch pens, scissors, adhesive, cardboard.

Procedure:

1. Collect data from day to day life such as weights of students in a class and

make a frequency distribution table.

Case I : For classes of equal widths.

C-I	10-20	20-30	30-40	40-50	50-60
Frequency	50	10	30	20	50

Case II : For classes of varying widths

C-I	10-20	20-40	40-60
Frequency	50	40	70

2. Take a graph paper ( 20 cm × 20 cm) and paste it on a cardboard.

3. Draw two perpendicular axes X'OX and YOY' on the graph paper.

4. Mark classes on x-axis and frequencies on y-axis at equal distances as shown in Fig. 1.

Figure 1

5. Draw the histogram for case-1 as shown in figure 2

Figure 2

6. For the case-2 width of class interval are not equal. So first of all we adjust the frequency by using the formula.

 

7. Draw the histogram for the case 2 as shown in the figure 2

Figure 3

Observations

For Case 1: We take class interval along the x-axis and frequencies along the y-axis. We find the continuous graph which is called Histogram.

For Case 2: Here Class intervals are continuous but class widths are not same. So first of all we need to adjust the frequency by using the formula.

So adjusted frequency table is become as below

C-I	Frequency	Adjusted Frequency
10-20	50
20-40	40
40-60	70

Result : 

In this activity we learn to made a Histogram for equal class widths and for for varying class widths.

Applications

Histograms are used in presenting large data in a concise form pictorially.

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