Statistics assignment question 1

Assignment-2

  1. Calculate the quartile deviation and its coefficient from the following data:

𝑿

6

12

18

24

30

36

42

𝒇

4

7

9

18

15

10

5

>

Calculate the quartile deviation and its coefficient from the following data:

Class

8-12

12-16

16-20

20-24

24-28

Frequency

5

12

20

10

3

>

Calculate the mean deviation about median for the following data:

π‘ͺ𝒍𝒂𝒔𝒔

0-10

10-20

20-30

30-40

40-50

50-60

60-70

𝒇

7

12

18

25

16

14

8

2.

3.

  1. Compute the mean deviation about the mean from the following distribution of the scores of 50 college students:

𝑺𝒄𝒐𝒓𝒆𝒔

140-150

150-160

160-170

170-180

180-190

190-200

𝒇

4

6

10

18

9

3

  1. For a group of 20 items, ∑𝑋 = 1452 and ∑𝑋2 = 144280. Find the standard deviation and coefficient of variation.
  2. Determine the standard deviation and coefficient of variation from the following data.

π‘ͺ𝒍𝒂𝒔𝒔

3.0-3.5

3.5-4.0

4.0-4.5

4.5-5.0

5.0-5.5

5.5-6.0

6.0-6.5

6.5-7.0

𝒇

2

6

12

15

16

10

5

2

  1. (a) The standard deviation of a set of 50 items if 6.5. Find the standard deviation, if every item is increased by 5.
    • Find the coefficient of variation, if the sum of the squares of the deviations of 10 observations taken from the mean 50 is 250.
    • The standard deviation of a set of 50 items is 8. Find the standard deviation, if each item is multiplied by 2.

Measure of Dispersion

  1. During the 10 weeks of a session, the marks obtained by two candidates, Ramesh and Suresh, taking the Computer Programme are given below:

Ramesh

58

59

60

54

65

66

52

75

69

52

Suresh

87

89

78

71

73

84

65

66

56

46

  • Who is better scorer- Ramesh or Suresh?
  • Who is more consistent?
  1. The following table gives heights of boys and girls in a college:

Boys

Girls

Numbers

400

100

Average Height

68 inches

65 inches

Variance

9

4

  • Find standard deviation of the heights of boys and girls taken together.
  • Whose heights are more variable?
  1. If standard deviation is 18.5, Calculate quartile deviation and mean deviation.