Advertisements
Advertisements
Question
The mean and standard deviations of two brands of watches are given below:
| Brand-I | Brand-II | |
| Mean | 36 months | 48 months |
| S.D. | 8 months | 10 months |
Calculate a coefficient of variation of the two brands and interpret the results.
Advertisements
Solution
Here, `bar("x"_"I") = 36, bar("x"_"II") = 48, sigma_"I" = 8, sigma_"II" = 10`
C.V. (I) = `100 xx sigma_"I"/bar("x"_"I") = 100 xx 8/36` = 22.22%
C.V. (II) = `100 xx sigma_"II"/bar("x"_"II") = 100 xx 10/48` = 20.83%
Since, C.V. (I) > C.V. (II)
∴ brand I is more variable.
APPEARS IN
RELATED QUESTIONS
Calculate coefficient of variation of marks secured by a student in the exam, where the marks are: 2, 4, 6, 8, 10.
(Given: `sqrt8` = 2.8284)
Find the coefficient of Variation of a sample which has mean equal to 25 and standard deviation of 5.
A group of 65 students of class XI have their average height is 150.4 cm with coefficient of variation 2.5%. What is the standard deviation of their height?
Two workers on the same job show the following results:
|
Worker P |
Worker Q | |
| Mean time for completing the job (hours) | 33 | 21 |
| Standard Deviation (hours) | 9 | 7 |
Regarding the time required to complete the job, which worker is more consistent?
Two workers on the same job show the following results:
| Worker P | Worker Q | |
| Mean time for completing the job (hours) | 33 | 21 |
| Standard Deviation (hours) | 9 | 7 |
Which worker seems to be faster in completing the job?
A company has two departments with 42 and 60 employees respectively. Their average weekly wages are Rs. 750 and Rs. 400. The standard deviations are 8 and 10 respectively. Which department has a larger bill?
A group of 65 students of class XI have their average height is 150.4 cm with coefficient of variance 2.5%. What is the standard deviation of their height?
Two workers on the same job show the following results:
| Worker P | Worker Q | |
| Meantime for completing the job (hours) | 33 | 21 |
| Standard Deviation (hours) | 9 | 7 |
- Regarding the time required to complete the job, which worker is more consistent?
- Which worker seems to be faster in completing the job?
A company has two departments with 42 and 60 employees respectively. Their average weekly wages are Rs. 750 and Rs. 400. The standard deviations are 8 and 10 respectively: Which department has a larger bill?
The following table gives weights of the students of two classes. Calculate the coefficient of variation of the two distributions. Which series is more variable?
| Weight (in kg) | Class A | Class B |
| 30-40 | 22 | 13 |
| 40-50 | 16 | 10 |
| 50-60 | 12 | 17 |
Answer the following :
Following data relates to the distribution of weights of 100 boys and 80 girls in a school:
| Boys | Girls | |
| Mean | 60 | 47 |
| Variance | 16 | 9 |
Which of the two is more variable?
Answer the following :
The mean and standard deviations of two bands of watches are given below :
| Brand-I | Brand-II | |
| Mean | 36 months | 48 months |
| S.D. | 8 months | 10 months |
Calculate coefficient of variation of the two brands and interpret the results
Answer the following :
Calculate coefficient of variation for the data given below:
| Income (Rs.) |
3000 - 4000 | 4000 - 5000 | 5000 - 6000 | 6000 - 7000 | 7000 - 8000 | 8000 - 9000 | 9000 - 10000 |
| No. of families | 24 | 13 | 15 | 28 | 12 | 8 | 10 |
Answer the following :
There are two companies U and V which manufacture cars. A sample of 40 cars each from these companies are taken and the average running life (in years) is recorded
| Life (in years) | No of Cars | |
| Company U | Company V | |
| 0 - 5 | 5 | 14 |
| 5 - 10 | 18 | 8 |
| 10 - 15 | 17 | 18 |
Which company shows greater consistency?
In a series of observations, coefficient of variation is 25 and mean is 20, then the variance is ______.
