Final answer:
The question pertains to completing a CSS code snippet to change the background color of a table row on hover. The completed code uses the :hover pseudo-class to apply a purple background color when a row within a table classed as 'schedule' is hovered over by the mouse.
Step-by-step explanation:
The code snippet you've provided is CSS, which is used to style HTML elements on web pages. To complete the code so that it changes the background color of a table row when the mouse hovers over it, we should target the table row within the .schedule class and then use the :hover pseudo-class to apply the style only when it's hovered over. Here's the completed code:
table.schedule tr:hover {
background-color: #80045f;
}
This code will apply a purple (#80045f) background to any row within a table with the class schedule when the mouse cursor is over it.