# 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: 𝑪𝒍𝒂𝒔𝒔 0-10 10-20 20-30 30-40 40-50 50-60 60-70 𝒇 7 12 18 25 16 14 8

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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.
 𝑪𝒍𝒂𝒔𝒔 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.