Creating a Freq. Dist. Using Grouped Quantitative

Data (Histogram)

o Number of classes should ideally be between 4 and 20

▪ One method to determine the number of classes is

• 2k n, where k = number of classes, n = number

of data points

▪ once k is known, the width is found by:

• Estimated class width = (Max data value –

minimum data value)/k

o Round to whole number

• Class boundaries – the minimum and maximum values for each

class

o choose class boundaries that are easy to read

*Rules for Classes for Grouped Data*

1. Equal-size classes.

2. Mutually exclusive classes: class boundaries cannot

overlap.

3. Include all data values.

4. Avoid empty classes.

5. Avoid open-ended classes: infinite.

• Some data are technically discrete but displayed in a

continuous format

find more resources at oneclass.com

find more resources at oneclass.com