4. Data Validation and Dropdown Lists

Data Validation stops people from typing just anything into a cell:

• List: the cell gets a ▾ arrow and you pick a value from the list. The source is a range, for example $F$2:$F$4;
• Whole number between … and …: for example, a rating from 1 to 5.

Select the cells, click Data Validation and set the rule. Then try typing a wrong value: the trainer, like Excel, will not accept it.