NameError: name 'mode' is not defined

The error message "NameError: name 'mode' is not defined" occurs when you try to use the variable or function named "mode" without first defining it in your code.

For example, if you try to use the mode function from the statistics module in Python, you need to import the module and then call the function like this:

import statistics
data = [1, 2, 2, 3, 3, 3, 4, 4, 5]
mode = statistics.mode(data)
print(mode)

If you don't import the module or define the function yourself, you will get the "NameError: name 'mode' is not defined" error message.