Topics
Number Systems
Number Systems
Polynomials
Algebra
Coordinate Geometry
Linear Equations in Two Variables
Geometry
Coordinate Geometry
Introduction to Euclid’S Geometry
Mensuration
Statistics and Probability
Lines and Angles
- Introduction to Lines and Angles
- Basic Terms and Definitions
- Intersecting Lines and Non-intersecting Lines
- Introduction to Parallel Lines
- Pairs of Angles
- Parallel Lines and a Transversal
- Angle Sum Property of a Triangle
Triangles
- Concept of Triangles
- Congruence of Triangles
- Criteria for Congruence of Triangles
- Properties of a Triangle
- Some More Criteria for Congruence of Triangles
- Inequalities in a Triangle
Quadrilaterals
- Concept of Quadrilaterals
- Properties of a Quadrilateral
- Types of Quadrilaterals
- Another Condition for a Quadrilateral to Be a Parallelogram
- Theorem of Midpoints of Two Sides of a Triangle
- Property: The Opposite Sides of a Parallelogram Are of Equal Length.
- Theorem: A Diagonal of a Parallelogram Divides It into Two Congruent Triangles.
- Theorem : If Each Pair of Opposite Sides of a Quadrilateral is Equal, Then It is a Parallelogram.
- Property: The Opposite Angles of a Parallelogram Are of Equal Measure.
- Theorem: If in a Quadrilateral, Each Pair of Opposite Angles is Equal, Then It is a Parallelogram.
- Property: The diagonals of a parallelogram bisect each other. (at the point of their intersection)
- Theorem : If the Diagonals of a Quadrilateral Bisect Each Other, Then It is a Parallelogram
Circles
Areas - Heron’S Formula
Surface Areas and Volumes
Statistics
Algebraic Expressions
Algebraic Identities
Area
Constructions
- Introduction of Constructions
- Basic Constructions
- Some Constructions of Triangles
Probability
Notes
Collecting Data:
Temperatures of cities as on 20.6.2006 |
||
City |
Max. |
Min. |
| Ahmedabad | 38°C | 29°C |
| Amritsar | 37°C | 26°C |
| Bangalore | 28°C | 21°C |
| Chennai | 36°C | 27°C |
| Delhi | 38°C | 28°C |
| Jaipur | 39°C | 29°C |
| Jammu | 41°C | 26°C |
| Mumbai | 32°C |
27°C |
What do these collections of data tell you?
The data about the temperatures of cities can tell us many things, For example, you can say that the highest maximum temperature was in Jammu on 20.06.2006 but it cannot tell us the city which had the highest maximum temperature during the year. To find that, we need to collect data regarding the highest maximum temperature reached in each of these cities during the year. In that case, the temperature chart of one particular date of the year, as given in the table will not be sufficient. This shows that a given collection of data may not give us specific information related to that data.
For this, we need to collect data keeping in mind that specific information. In the above case, the specific information needed by us was about the highest maximum temperature of the cities during the year, which we could not get from the Table. Thus, before collecting data, we need to know what we would use it for.
-
When the information was collected by the investigator herself or himself with a definite objective in her or his mind, the data obtained is called primary data.
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When the information was gathered from a source which already had the information stored, the data obtained is called secondary data.
Such data, which has been collected by someone else in another context, needs to be used with great care ensuring that the source is reliable.
