Section2.1

Frequency Distribution

A table that organizes data by listing categories along with the frequency of data values in each category.

Lower Class Limits

The smallest numbers that can belong to each of the different classes.

Upper Class Limits

The largest numbers that can belong to each of the different classes.

Class Boundaries

The numbers used to separate classes without gaps created by class limits.

Class Midpoints

The values in the middle of the classes, calculated by taking the average of the lower and upper class limits.

Class Width

The difference between two consecutive lower class limits or class boundaries.

Cumulative Frequency Distribution

A distribution that shows the frequency for each class as the sum of the frequencies for that class and all previous classes.

Relative Frequency Distribution

A distribution that replaces each class frequency with the relative frequency or percentage of the total.

Normal Distribution

A distribution where frequencies start low, increase to a maximum, and then decrease to low again, creating a symmetric shape.

Gaps in Data

The presence of gaps can indicate that the data are from two or more different populations.