NCERT Book Class 11 Statistics Measures of Dispersion

EXERCISES

1. A measure of dispersion is a good supplement to the central value in understanding a frequency distribution. Comment.

2. Which measure of dispersion is the best and how?

3. Some measures of dispersion depend upon the spread of values whereas some calculate the variation of values from a central value. Do you agree?

4. In a town, 25% of the persons earned more than Rs 45,000 whereas 75% earned more than 18,000. Calculate the absolute and relative values of dispersion.

5. The yield of wheat and rice per acre for 10 districts of a state is as under:

District 1 2 3 4 5 6 7 8 9 10

Wheat 12 10 15 19 21 16 18 9 25 10

Rice 22 29 12 23 18 15 12 34 18 12

Calculate for each crop,

(i) Range

(ii) Q.D.

(iii) Mean Deviation about Mean

(iv) Mean Deviation about Median

(v) Standard Deviation

(vi) Which crop has greater variation?

(vii)Compare the values of different measures for each crop.

6. In the previous question, calculate the relative measures of variation and indicate the value which, in your opinion, is more reliable.

7. A batsman is to be selected for a cricket team. The choice is between X and Y on the basis of their five previous scores which are:

X 25 85 40 80 120

Y 50 70 65 45 80

Which batsman should be selected if we want,

(i) a higher run getter, or

(ii) a more reliable batsman in the team?

8. Averge daily wage of 50 workers of a factory was Rs 200 with a Standard Deviation of Rs 40. Each worker is given a raise of Rs 20. What is the new average daily wage and standard deviation? Have the wages become more or less uniform?

9. If in the previous question, each worker is given a hike of 10 % in wages, how are the Mean and Standard Deviation values affected?

Please refer to attached file for NCERT Class 11 Statistics Measures of Dispersion