What is the difference between absolute and relative measures of dispersion?

Absolute vs. Relative Dispersion

• Absolute measures depend on units.

• Includes range and standard deviation.

• Relative measures are unit-free.

Fill in the blank: The range of a dataset is calculated as the difference between the ___ and ___ values.

Largest and smallest

Why is the mean deviation considered a more effective measure of dispersion than range?

Mean deviation accounts for all data points, providing a more comprehensive view of variability, whereas range only considers two extreme values.

True or False: The coefficient of variation is defined as the ratio of standard deviation to the mean, expressed as a percentage.

True

What is the ideal characteristic of a measure of dispersion?

A measure of dispersion must be clear.

• Defines variability in data.

• Helps in data interpretation.

• Supports statistical analysis methods.

Riddle: I am a measure of spread, but I rely on just two points. What am I?

The range

How do you compute the coefficient of mean deviation about the median?

It is calculated as the mean deviation about the median divided by the median, multiplied by 100.

Fill in the blank: The standard deviation is defined as the root mean square deviation from the ___ of observations.

Arithmetic mean

What is the relationship between the mean deviations of related variables, such as x and y in the equation 2x + 3y = 10?

The mean deviation of y can be computed as |b| times the mean deviation of x, where b is the coefficient of x in the equation.

In what situation is quartile deviation considered the best measure of dispersion?

Quartile deviation is preferred in open-end classifications, as it is less affected by extreme observations.

True or False: The standard deviation cannot be treated mathematically like the mean deviation.

True

What does the coefficient of quartile deviation measure?

It measures relative dispersion based on the first and third quartiles of a dataset.

Fill in the blank: If the mean of a dataset is 50 and the standard deviation is 5, then the coefficient of variation is ___%.

10

How is the combined standard deviation of two groups calculated?

It involves using the means and standard deviations of both groups to find a weighted average that considers the number of observations in each group.

Riddle: I can change if you shift the origin or change the scale, but I reflect the spread of data. What am I?

Standard deviation