AHSEC| CLASS 12| EDUCATION| CHAPTER - 7| EDUCATIONAL STATISTICS| SOLVED QUESTIONS FOR 2 MARK EACH| H.S. 2ND YEAR

EDUCATIONAL STATISTICS

Solved questions for 2 mark each:

1. What is frequency? Exam paper - 2017

Ans: Frequency refers to the number of times a particular value appears in a distribution. For example, in the distribution of values, 4, 5, 5, 6, 5, 4, 5 has a frequency of 3, 4 has a frequency of 2, and 6 has a frequency of 1.

2. What do you understand by class interval?

Ans: The size of the class interval is determined by taking into account the total number of values in a given distribution of data.

3. What are representational graphs?

Ans: It is a pictorial representation of an event for which it holds credibility and objectivity. This can be done by means of frequency polygon, histogram, cumulative frequency graph and cumulative percentage treatment or pylon.

4. Write the formula for finding out Median from group data? Exam paper - 2014

5. Why is a histogram called a continuous bar graph?

Ans: A histogram is called a continuous bar graph because the frequency distribution makes the class intervals uniform.

6. What is a frequency distribution table?

Ans: Frequency Distribution Table: The table where the raw scores are systematically arranged may be known as 'Frequency Distribution Table'. In a frequency distribution table, there are three columns which are class interval, tally mark and frequency. The range of the variable in a particular sub-category is called the class-interval and the number of items in a class-interval is known as the class frequency. The distribution in the form of class frequencies on class intervals is called frequency distribution of variables.

7. What is pie diagram? Exam paper - 2018, 2019

Ans. When a circle is sub-divided into different sectors to represent different data it is called a pie-diagram. To represent the data by pie-diagram we first draw a circle with any radius. The angle at the center of the circle is 360 degrees which represents the set. It can be divided into several smaller angles whose degrees will be proportional to the values of the components. The angle representing each item or sector can be calculated with the help of the following formula

Suppose, in a college there are 120 students in arts faculty and 60 students in science faculty. If the values are represented by a pie-diagram, then the angle

8. What are the first quartile and third quartile?

Ans: Q₁ is the 25th percentile above the 25th percentile of the median at half the distance between Q₃ and Q₁.

Q₃ is the 75th percentile or the 3rd percentile.

9. Which measure of central tendency would apply - when maximum stability is required?

Ans: Mean.

10. What is meant by central tendency of the set of scores obtained?

Ans: Quantitative data show a general characteristic to concentrate on some value, usually somewhere in the center of the distribution. So, there is a specific value that can represent all the data in a series. The value around which the values of a distribution cluster is called the measure of central tendency. The arithmetic mean is an important measure of central tendency.

11. Given the following sets of score. Calculate the range for each set.

Set - I	15,12,18,22,5,27,8,35
Set - II	45, 52, 33, 42, 23, 58, 70, 79, 56

Ans:- Set – I 35-5=30

Set – II 79-23=56

12. Write two differences between polygon and histogram. Exam paper - 2014, 16, 19

Ans: Histogram: The totality of all the rectangles drawn on a horizontal line with areas proportional to the frequencies of the respective class intervals is called a histogram.

Frequency Polygon: The data collected and tabulated can be represented graphically with the help of frequency polygons. To draw a frequency polygon, a baseline has to be drawn first. Let the base line be 'X'. Then a vertical line named 'Y' should be drawn on the left side. Then we plot the mind-points of the class-interval along the line Y. By joining the points, we will get the frequency polygon.

13. Write two properties of mean.

Ans: Properties:

(i) The definition of mean is clear and rigid.

(ii) It is easy to understand and easy to calculate.

(iii) All the items in the series are taken into account in computing the mean.

(iv) It can be calculated even when the total and the number of items is given.

(v) It can be subjected to further algebraic treatment.

14. Write two demerits of median. Exam paper - 2016

Ans: Demerits:

(i) Rearranging the data may be necessary to calculate the median.

(ii) It is difficult to calculate the median for a continuous series.

(iii) Median does not have mathematical properties.

(iv) It does not take into account all the items in the series. Hence it is not a true representative of the values of the variable.

15. Which is the most volatile central tendency?

Ans: Mode is the most unstable central tendency.

16. Which is the positional measure of central tendency? Exam paper - 2017

Ans: Median is a positional measure of central tendency.

17. Which measure of Central tendency affected most by extreme observation? Exam paper - 2013

Ans: The measure of central tendency most affected by extreme observations is the median.

18. From a batch of 13 students who had appeared for an examination 4 students had failed. The marks of the successful students were - 41, 57, 38, 61, 35, 39, 75, 50, 45. Calculate the Median. Exam paper - 2016

19. In a histogram the class intervals are taken along - X-Axis/ Y-Axis.

Ans: In a histogram the class intervals are taken along x-Axis (x Axis/ y-Axis)

20. Given Mean is 25, Mode is 24, the Median would be

21. The mean of five numbers is 27. If one number is excluded, their mean is 25. Find the excluded number. Exam paper - 2015

22. Find the Median of the following data: 41, 43, 125, 99, 61, 92, 71, 58, 57. If 58 is replaced by 85. What will be the new median?

23. Which is the most unstable central tendency?

Ans: Mode is the most unstable central tendency.

24. Which is the positional measure of central tendency? Exam paper - 2015

Ans: Mean is a positional measure of central tendency.

25. Which measure of central tendency is most affected by excess observation?

Ans: The mean is the measure of central tendency that is most affected by extreme observations.

26. From a batch of 15 students who had appeared for an examination 5 students had failed. The marks of the successful students were 41, 58, 45, 63, 75, 62, 67, 54, 43, 72. Calculate the median.

27. What is quartile deviation?

Ans: The quartile deviation or Q is half of the difference between the 75th and 25th percentiles in a frequency distribution.

28. Write the formula to find the range.

Ans: The formula to find the range is -

Rank = (highest score - lowest score)

29. What is central tendency? Exam paper - 2019

Ans: In most frequency distributions, the points are concentrated near the center of the distribution. This tendency is known as the central tendency or average of the series.

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