8th Class Mental Ability Data Handling Notes - Statistics

Statistics

Learning Objectives

• Data Handing
• Introduction to Graphs

Data Handling

• Pictograph: A pictograph is a way of showing data using images.
• The number of times that a particular entry occurs in a data is called its frequency.
• In the class interval, 10-20, 10 is called the lower class limit and 20 is called the upper class limit.
• The difference between the upper class limit and lower class limit is called the width or size of the class interval.

Introduction to Graphs

• Bar Graph: It is a display of information using bars of uniform width, their heights being proportional to the respective values.
• Double Bar Graph: It is a type of bar graph showing two sets of data simultaneously. It is useful for the comparison of the data.
• Histogram: A histogram is a bar graph that shows data in intervals. It has adjacent bars over the continuous intervals.
• Pie graph: The representation of data on a pie chart is called a pie graph. It is used to compare parts of a whole.
• A line graph displays data that changes continuously over periods of time. It is a whole unbroken line.
• For fixing a point on the graph sheet we need, x-coordinate and y-coordinate.
• The relation between dependent variable and independent variable is shown through a graph.

Commonly Asked Questions

1. Observe the following histogram and answer the questions.

2. What information is being given by the graph?

(a) Height of the students of class 8          

(b) Number of students in class 8

(c) Weight of the students of class 8          

(d) All of these

(e) None of these

3. The following pie-chart represents the expenditures of a family on different items. What percent of total expenditure is spent by the family on housing?

(a) 61%                         (b) 16.7%

(c) 13.9%                       (d) 12.7%

(e) None of these

Answer: (b)

Explanation: Percentage expenditure on housing  \[=\frac{60{}^\circ \times 100}{360{}^\circ }=16.7%\]