Measures of Dispersion

Author:Maharashtra Board
11th Maharashtra Board
IMPORTANT

Important Questions on Measures of Dispersion

HARD
IMPORTANT

The mean of 5 observations is 4.8 and the variance is 6.56. If three of the five observations are 1,3 and 8, find the other two observations.

HARD
IMPORTANT

Following data gives age of 100 students in a college. Calculate variance and S.D.

Age(In year) 16 17 18 19 20 21
No. of student 20 7 11 17 30 15

 

HARD
IMPORTANT

Compute the variance and S.D.

x 31 32 33 34 35 36 37
Frequency 15 12 10 8 9 10 6

 

HARD
IMPORTANT

Compute variance and standard  deviation for the following data:

X 2 4 6 8 10 12 14 16 18 20
F 8 10 10 7 6 4 3 4 2 6

HARD
IMPORTANT

Find variance and S.D. for the following set of numbers.

65, 77, 81, 98, 100, 80, 129

MEDIUM
IMPORTANT

Find variance and S.D. for the following set of numbers.

7, 11, 2, 4, 9, 6, 3, 7, 11, 2, 5, 8, 3, 6, 8, 8, 2, 6

HARD
IMPORTANT

Compute coefficient of variation for team A and team B.

No. of goals  0 1 2 3 4
No. of matches played by team A 19 6 5 16 14
No. of matches played by team B 16 14 10 14 16

 

HARD
IMPORTANT

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

 

EASY
IMPORTANT

The standard deviation of a distribution divided by the mean of the distribution and expressing in percentage is called:

EASY
IMPORTANT

If the observations of a variable X are, 4, 20, 30, 44 and 36, then the value of the range will be:

MEDIUM
IMPORTANT

Given below is the information about marks obtained in Mathematics and Statistics by 100 students in a class. If the coefficient of variation of the subject showing the highest variability in marks is k% then find the value of k.

  Mathematics statistics
Mean 20 25
S.D. 2 3

 

MEDIUM
IMPORTANT

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(in cm)?

HARD
IMPORTANT

Calculate coefficient of variation correct up to second decimal place of marks secured by a student in the exam, where the marks are: 85, 91, 96, 88, 98, 82

HARD
IMPORTANT

For a certain data, following information is available.

  X Y
Mean 13 17
S.D. 3 2
Size 20 30

Obtain the combined standard deviation rounding off upto second decimal places.

MEDIUM
IMPORTANT

The means of two samples of sizes 60 and 120 respectively are 35.4 and 30.9 and the standard deviations 4 and 5. Obtain the standard deviation of the sample of size 180 obtained by combining the two sample correct upto two decimal places.

EASY
IMPORTANT

Find range for the following data.

Classes 62-64 64-65 66-68 68-70 70-72
Frequency 5 3 4 5 3

EASY
IMPORTANT

Following results were obtained by rolling a die 25 times. Find the range of the data.

Score 1 2 3 4 5 6
Frequency 4 6 2 7 3 3

EASY
IMPORTANT

The following data gives the number of typing mistakes done by Radha during a week. Find the range of the data.

Day Monday Tuesday Wednesday Thursday Friday Saturday
Number of mistakes 15 20 21 12 17 10

EASY
IMPORTANT

Find the range of the following data:

575, 609, 335, 280, 729, 544, 852, 427, 967, 250.

EASY
IMPORTANT

Find the range of the following data:

19, 27, 15, 21, 33, 45, 7, 12, 20, 26.