The company doesn’t have any employees below 20 years of age. Anyone who has not yet passed his 30^th birthday belongs to the 20-30 group. Anyone who has passed their 30^th birthday, even by one day, but has not yet reached the age of 40, belongs to the 30-40 group. Anyone whose 30^th, 40^th, 50^th, or 60^th birthday falls exactly on the day that they fill out the questionnaire is told to consider themselves in the younger age group.

For example, an employee who turned 30 on the day she completed the questionnaire would be included in the 20-30 group, and not the 30-40 group.

The student randomly compiles the answers to the questionnaires in the following table:

Each row in the table is called an observation. A collection of observations comprises a sample. This table represents the sample. In this case, the sample includes 30 observations. The information found in the sample is very specific and includes very specific details. When the student wishes to investigate, for example, only the gender of employees, they will prefer to arrange a new, shorter, and more informative table, as we will soon see.

The Crude Data