EXERCISE 7.1 | TS-CLASS 8TH-MATHS-CHAPTER 7-FREQUENCY DISTRIBUTION TABLES AND GRAPHS || скачать в хорошем качестве

EXERCISE 7.1 | TS-CLASS 8TH-MATHS-CHAPTER 7-FREQUENCY DISTRIBUTION TABLES AND GRAPHS ||

Full exercise 7.1 has been solved in an easy and simple manner. It includes solution of questions from Question 1 to 20. Questions: 00:00 Q1. Find the arithmetic mean of the sales per day in a fair price shop in a week. Rs.10000, Rs.10250, Rs.10790, Rs.15350, Rs.10110 06:54 Q2. Find the mean of the data 10.25, 9, 4.75, 8, 2.65, 12, 2.35 11:47 Q3. Mean of eight observations is 25. If one observation 11 is excluded, find the mean of the remaining. 13:32 Q4. Arithmetic mean of nine observations is calculated as 38. But in doing so, mistakenly the observation 27 is taken instead of 72. Find the actual mean of the data. 15:25 Q5. Five years ago mean age of a family was 25 years. What is the present mean age of the family? 20:48 Q6. Two years ago the mean age of 40 people was 11 years. Now a person left the group and the mean age is changed to 12 years. Find the age of the person who left the group. 23:25 Q7. Find the sum of deviations of all observations of the data 5, 8, 10, 15, 22 from their mean. 25:33 Q8. If sum of the 20 deviations from the mean is 100, then find the mean deviation. 26:30 Q9. Marks of 12 students in a unit test are given as 4, 21, 13, 17, 5, 9, 10, 20, 19, 12, 20, 14. Assume a mean and calculate the arithmetic mean of the data. Assume another number as mean and calculate the arithmetic mean again. Do you get the same result? Comment. 33:25 Q10. Arithmetic mean of marks (out of 25) scored by 10 students was 15. One of the student named Karishma enquired the other 9 students and find the deviations from her marks are noted as -8, -6, -3, -1, 0, 2, 3, 4, 6. Find Karishma’s marks. 36:22 Q11. The sum of deviations of ‘n’ observatioins from 25 is 25 and sum of deviations of the same ‘n’ observations from 35 is -25. Find the mean of the observations. 38:09 Q12. Find the median of the data: 3.3, 3.5, 3.1, 3.7, 3.2, 3.8. 40:22 Q13. The median of the following observations, arranged in ascending order is 15, 10, 12, 14, x-3, x, x+2, 25. Then find x. 41:47 Q14. Find the mode of 10, 12, 11, 10, 15, 20, 19, 21, 11, 9, 10. 43:27 Q15. Mode of certain scores is x. If each score is decreased by 3, then find the mode of the new series. 45:21 Q16. Find the mode of all digits used in writing the natural numbers from 1 to 100. 47:41 Q17. Observations of a raw data are 5, 28, 15, 10, 15, 8, 24. Add four more numbers so that mean and median of the data remain the same but mode increases by 1. 54:40 Q18. If the mean of a set of observations x1, x2, ...., ..., x10 is 20. Find the mean of x1+4, x2+8, x3+12, ..., ..., x10+40. 58:02 Q19. Six numbers from a list of nine integers are 7, 8, 3, 5, 9 and 5. Find the largest possible value of the median of the median of all nine numbers in this list. 59:42 Q20. The median of a set of 9 distinct observations is 20. If each of the largest 4 observations of the set is increased by 2, find the median of the resulting set.