For more on differentiating between a population and a sample, you can check out this Khan Academy video:

For more on working with categorical (sometimes called qualitative) data and how it differentiates from numerical data (sometimes called quantitative):

All Khan Academy videos are offered by Khan Academy and are licensed under CC BY-NC-SA 3.0 unless otherwise noted.

For more, you can check out this these Khan Academy videos on the same topics:

Creating a pie chart

Creating a histogram

And more about sampling techniques:

And here is a good example of someone calculating both relative and cumulative frequency:

And here are some similar resources from Khan Academy covering experimental design concepts.

"Cumulative Frequency" video was created by Maths4Everyone (Links to an external site.)Links to an external site. and is being shared under a Standard YouTube License. (Links to an external site.)Links to an external site.

All Khan Academy videos are offered by Khan Academy and are licensed under CC BY-NC-SA 3.0 unless otherwise noted.