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# Statistics CBSE Class 9

## Full fledge assessment Videos

Video Based Test funda (Please watch the above videos before attempting this assessment)
Question 1/20

Q 1. The mean of 200 items was 50. Later, it was discovered that two items were misread as 92 and 8 instead of 192 and 88. Find the correct mean.

Solution

Mean of the data

50

Initial sum of all the observations = 50 × 200 = 10000

Corrected sum of all the observations = 10000 + 192 + 88 - 92 - 8 = 10180

Q 2. The mid-value of a class interval is 42. If the class size is 10, then the upper and lower limits of the class are

Solution

According to the question, 42 is a mid-value. Hence, the upper limit of the class interval is 42 + 5 = 47 and the lower limit of the class interval is 42 - 5 = 37.

Q 3. The class mark of the class 90-120 is

Solution

Class mark =  = 105

Q 4. There are ____ between the bars in a histogram.

Solution

Explanation: There are no gaps between the bars in a histogram.

Q 5. 3, 5, 6, 7, 3, 4, 6, 7, 8, 9, 3, 5, 6, 7, 8, 9. This data is

Solution

3, 5, 6, 7, 3, 4, 6, 7, 8, 9, 3, 5, 6, 7, 8, 9 is known as raw data.

Q 6. Histograms are based on the ___ and not on the height of bars.

Solution

Histograms are based on the area and not on the height of bars.

Q 7. Tally marks are used to find

Solution

Tally marks are used to find frequency.

Q 8. Students obtained the following marks in a test: 81, 72, 90, 90, 86, 85, 90, 70, 60, 55, 80 The range of marks is

Solution

The maximum value of the data is 90 and the minimum value of the data is 70.

The range is 90 - 55 = 35.

Q 9. The mid-value of a class interval is 42. If the class size is 10, then the upper and lower limits of the class are

Solution

According to the question,

42 is the mid-value. Hence, the upper limit of the class interval is 42 + 5 = 47 and the lower limit of the class interval is 42 - 5 = 37.

Q 10. Which of the following is not a type of statistical data?

Solution

Continuous data is not a type of statistical data.

Q 11. In the ‘less than’ type of ogive, the cumulative frequency is plotted against

Solution

In the ‘less than’ type of ogive, the cumulative frequency is plotted against the upper limit of the concerned class interval.

Q 12. Students obtained the following marks in a test: 81, 72, 90, 90, 86, 85, 90, 70, 60, 55, 80 The range of the marks is

Solution

The maximum value of the data is 90 and the minimum value of the data is 70.

The range is 90 - 55 = 35.

Q 13. Data arranged in the ascending or descending order is called

Solution

Data arranged in the ascending or descending order is called arrayed data.

Q 14. The class mark of class 90-120 is

Solution

Class mark = = 105

Q 15. Find the mean of the given data: 46.4, 29.3, 48.2, 35.1, 46.4, 39.5, 41.3, 25.2

Solution

Mean of the data

Q 16. In the class intervals 10-20 and 20-30, 20 belongs to

Solution

In the class intervals 10-20 and 20-30, 20 belongs to the interval 20-30.

Q 17. Which of the following is the disadvantage of arithmetic mean?

Solution

Arithmetic progression is sensitive to extreme values, especially when the sample size is small.

Q 18. Find the mode of the following data: 39, 40, 40, 41, 42, 46, 48, 52, 52, 52, 54, 60, 62, 96, 98

Solution

39, 40, 40, 41, 42, 46, 48, 52, 52, 52, 54, 60, 62, 96, 98

Mode of statistical data is the value of the variable which has the maximum frequency.

The mode of the given data is 52 since its frequency is 3.

Q 19. Which of the following is a type of statistical data?

Solution

Primary and secondary data are types of statistical data.

Q 20. Find the median of the following data: 39, 40, 40, 41, 42, 46, 48, 52, 52, 52, 54, 60, 62, 96, 98

Solution

Arranging the data in the ascending order:

39, 40, 40, 41, 42, 46, 48, 52, 52, 52, 54, 60, 62, 96, 98

Here, n = 15 … (odd)

Median = = = 8th term = 52

Still have doubt?

## Statistics Notes

#### Revision Notes

Read CBSE Class 9 Mathematics revision notes for Statistics

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## Statistics Doubts and Solutions

Asked by Vvirattiger2003 2nd April 2019, 4:53 AM
Asked by rimpy1908 15th February 2019, 8:03 PM
Asked by sarvanhi1108 16th January 2019, 11:42 AM