Quantitative Data Analysis

The most common way of presenting data is:
FREQUENCY DISTRIBUTIONS AND HISTOGRAMS

TERMINOLOGY
FREQUENCY: The number of data in a class.
RELATIVE FREQUENCY: The percentage of all data values ​​that are in a class.
HISTOGRAM: The graphical presentation of (relative) frequencies

FREQUENCY DISTRIBUTION: CONSTRUCTION

1. Divide the interval of available values ​​into a series of subintervals (classes)
2. Determine the number of data in each class

KEY POINTS IN CONSTRUCTING FREQUENCY DISTRIBUTIONS

1. Classes are used to give the correct picture of the distribution of the data (arbitrary definition, rule of thumb: 5-20 classes, usually more data -> more classes)
2. Determine the range of each class (rule of thumb: classes of equal width usually)
3. Determine the limits of the classes (measurements must be distributed in only 1 category)

Note: Grouping data leads to loss of information. The choice of the number and width of the classes leads to greater detail of the distribution.

Sturgess Type

Equal-sized classes r (The most common case)

The classes are calculated from intervals of the form: [ , ) or ( , ].

The classes must cover all the data.