Frequency Distribution Table | Week 3 & Week 5

Frequency Distribution Table

This table organizes raw data into classes (intervals) showing how many values fall into each class.

Class Interval (Class)

A group or range of numbers that represents a category in the table.

Class Limits

The smallest and largest data values that can belong to a class.

Class Boundaries

The true limits of each class — they remove gaps between consecutive classes.

Class Width

The distance or interval size between class limits (or boundaries).

Range

The difference between the highest and lowest data values.

Frequency (f)

The number of data values that fall within each class interval.

Class Mark (x or Midpoint)

The average of the lower and upper class limits.

Cumulative Frequency (cf)

The running total of frequencies as you move through classes.

Measure of Dispersion

Describes how spread out or scattered the data values are from the mean.

Variance

➤ The average of the squared deviations from the mean.
➤ Expressed in squared units of the original data.

Standard Deviation

➤ The square root of the variance.
➤ It tells how much each value deviates from the mean on average.

Sample Standard Deviation (Ungrouped Data)

➤ A measure of how much individual data values vary around the mean for sample data (not the whole population).

Sample Variance (Ungrouped Data)

➤ The average squared deviation of all sample values from the sample mean.