Measures of Dispersion Maths - Measures of Dispersion

The standard deviation of data is 12 and mean is 72, then the coefficient of variation is

Given the heights (in cm) of two groups of students:

Group A: 131 cm, 150 cm, 147 cm, 138 cm, 144 cm

Group B: 139 cm, 148 cm, 132 cm, 151 cm, 140 cm

Which of the following is/are true?

I. The ranges of the heights of the two groups of students are the same.

II. The means of the heights of the two groups of students are the same.

For any two numbers, SD is always

The variance of 19, 21, 23, 25 and 27 is 8. The variance of 14, 16, 18, 20 and 22 is:

The positive square root of the mean of the squares of the deviations of observations from their mean is called:

The means and S.D. of weights and heights of 100 students of a school are as follows.

Which shows more variability, weights, or heights?

The mean and standard deviations of the two brands of watches are given below:

Calculate the coefficient of variation of the two brands and interpret the results.

The following data relates to the distribution of weights of 100 boys and 80 girls in a school.

Which of the two is more variable?

Find variance and S.D. for the following set of numbers. 125, 130, 150, 165, 190, 195, 210, 230, 245, 260

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

25, 21, 23, 29, 27, 22, 28, 23, 21, 25

Calculate the coefficient of variation for the data given below:

Calculate the coefficient of variation of the following data.

23, 27, 25, 28, 21, 14, 16, 12, 18, 16

Calculate S.D. from the following data.

Following data gives no. of goals scored by a team in 90 matches. Compute the standard deviation.

The arithmetic mean of runs scored by 3 batsmen Varad, Viraj and Akhilesh in the same series are 50, 52 and 21 respectively. The standard deviation of their runs are 11, 16 and 5 respectively. Who is the most consistent of the three? If one of the three is to be selected, who will be selected?

Compute the coefficient of variations for the following data to show whether the variation is greater in the field or in the area of the field.

The mean height of 200 students is 65 inches. The mean heights of boys and girls are 70 inches and 62 inches respectively and the standard deviations are 8 and 10 respectively. Find the number of boys and combined S.D.

The mean and S.D. of a group of 50 observations are 40 and 5 respectively. If two more observations 60 and 72 are added to the set, find the mean and S.D. of 52 items.

Given below is the frequency distribution of marks obtained by 100 students. Compute arithmetic mean and S.D.

There are two companies U and V which manufacture cars. A sample of 40 cars each from these companies is taken and the average running life (in years) is recorded.

Which company shows greater consistency?

Calculate the coefficient of variation for the data given below:

The arithmetic mean and standard deviation of a series of 20 items were calculated by a student as 20 cm and 5 cm respectively. But while calculating them, item 13 was misread as 30. Find the corrected mean and standard deviation.

The first group has 100 items with mean 45 and variance 49. If the combined group has 250 items with mean 51 and variance 130, find the mean and standard deviation of second group.

Compute variance and standard deviation for the following data :

Find the range of the following data.

Given below is the frequency distribution of weekly wages of 400 workers. Find the range.

Find the range for the following data. 116, 124, 164, 150, 149, 114, 195, 128, 138, 203, 144

Find the range for the following data. 76, 57, 80, 103, 61, 63, 89, 96, 105, 72

The number of centuries scored in a year by seven randomly selected batsmen are

Find the Variance and Standard Deviation of these seven batsmen.

The marks scored in a test by seven randomly selected students are

Find the Variance and Standard Deviation of these seven students.