CBSE Class 9 Maths Extra Questions: Chapter 14 - Statistics (with Answers)
Get here extra questions (with answers) for CBSE Class 9 Maths Chapter 14 - Statistics. These questions are quite helpful to brush up all important concepts and thus make preparations for the exam in a better way. Therefore, students must try to solve each question in order to increase their chances of scoring high in the CBSE Class 9 Maths Exam 2020-21.
CBSE Class 9 Maths Extra Questions for Chapter 14 - Statistics:
1. What do you mean by primary and secondary data?
Primary data means the information was collected by an investigator herself or himself with a definite objective in her or his mind. It is also named as the 'first-hand information'.
Secondary data is the information gathered from a source which already had the information stored. It is also termed as ‘second-hand information’.
2. Find the range of the data given below that represents the marks obtained by students of a class.
55 36 95 73 60 42 25 78 75 62
Range = 70
Hint: The difference of the highest and the lowest values in the data is called the range of the data.
3. What is the mean value of a set of observations?
The mean (or average) of a number of observations is the sum of the values of all the observations divided by the total number of observations.
4. How do we calculate the median of given data?
The median is the middle number in a data set when the numbers are listed in either ascending or descending order. It can be calculated as follows:
5. What is the mode of a given set of data?
The mode is that value of the observation which occurs most frequently, i.e., an observation with the maximum frequency is called the mode.
6. The mean of 6 observations is 20. On removing one number from the given set, the mean of the remaining numbers becomes 16. Find the value of the removed number?
The value of the removed number = 40
7. The mean of a given set of observations is 30. If each observation is increased by 3, find the mean of the new observations.
The mean of the new observations = 90
Hint: On increasing each number by x, the mean of the new numbers becomes x times.
8. The mean of 21 observations is 32. If the mean of first 11 and last 11 observations is 23 and 28, then find the 11th observation.
The 11th observation = 111
Hint: (21 × 32) = [(11 × 23) + (11 × 28)] − 11th number
9. Find the median of the following numbers:
3, 4, 5, 6, 9, 8, 8, 11, 4
Median of given numbers = 6
Hint: The number of terms is odd so the median will be the middle term.
10. Find the mode of the following numbers:
9, 4, 17, 23, 4, 9, 11, 4, 17, 4, 23, 17, 7, 4, 11
Mode of given numbers = 4
Students must go through the latest CBSE Syllabus for Class 9 Maths so that they can prepare according to the contents prescribed by the board.