# GSEB Class 8 Maths Notes Chapter 5 Data Handling

This GSEB Class 8 Maths Notes Chapter 5 Data Handling covers all the important topics and concepts as mentioned in the chapter.

## Data Handling Class 8 GSEB Notes

→ A collection of numerical facts regarding particular type of information is called data.

→ To study data easily, it is represented by graphs.

→ A Pictograph: The pictorial representation of data using symbols is called pictograph.

→ A Bar Graph: A pictorial representation of numerical data in the form of rectangles (or bars) of uniform width and various heights is called a bar graph.

→ Histogram: A histogram is a graphical representation that organizes a group of data points into specific ranges. In histogram, the class intervals (width) are shown horizontal axis and heights of the bars show the frequency of the class interval, but there is no gap between the bars as there is no gap between the class intervals.

→ Double Bar Graph: A bar graph showing two sets of data simultaneously is called a double bar graph. It is useful for comparison of the data.

→ Pie Chart / Circle Graphs: It is a pictorial representation of the numerical data by non-intersecting adjacent sectors of a circle such that each sector is proportional to the information it represents.

→ Observation: Numerical information is called an observation.

→ Data: The collection of observations Is called data.

→ Raw data: A collection of observations gathered initially is called a raw data.

→ Frequency: The number of times a particular observation occurs is called its frequency.

→ Grouped Frequency distribution: It is the representation of grouped data in which frequencies are distributed over several classes (intervals).

→ Range: The difference between maximum and minimum observations of the raw data is called range.

→ Class interval: It is a specific small range in which various scores fall.

→ Class size: The difference between the upper and the lower class limits is called the width or class size of the class interval.

→ The data which is represented by diving a circle into sectors is known as pie chart.

→ Pie graphs are circular, so they are also called circle graphs.

→ Method of drawing pie graphs :

• From the given data, we find the total of the frequencies.
• For each variable, we calculate the angle of sector (i.e., the angle at the centre of the circle). This angle is called central angle.
Central angle for a variable = $$\frac{\text { Frequency of the variable }}{\text { Total of frequencies }}$$ × 360°
• We draw a circle of convenient radius.
• We draw the sectors corresponding to the central angle calculated in step (ii) above.
• Write down the names of variables and their corresponding central angles in the sectors. (Note: Sum of all the central angles is 360°.)

→ Probability: Probability is the measure of the chance of the happening of an event.

→ Experiment: An experiment is a situation involving chance or probability that leads to an outcome.

→ Outcomes: An outcome Is a result of a single trial of an experiment.

→ Events: An event is one or more outcomes of an experiment.

→ Probability = $$\frac{\text { Favourable outcomes }}{\text { Total outcomes }}$$