As you've learned, random assignment is essential to creating an independent variable. If we can't randomly assign participants to groups, we're not doing the experimental method. While those comparisons may still be valid, they're simply not experimental.

Below, you'll see a list of possible comparison groups. Two could realistically involve random assignment. Choose those two.

As you've learned, random assignment is essential to creating an independent variable. If we can't randomly assign participants to groups, we're not doing the experimental method. While those comparisons may still be valid, they're simply not experimental.

Below, you'll see a list of possible comparison groups. Two could realistically involve random assignment. Choose those two.

Nevin wants to compare laboratory cats assigned to eat wet food with laboratory cats assigned to eat dry food.

Teresa wants to compare men assigned to run a mile on a treadmill with men assigned to run a mile on an outdoor track.

Karina wants to compare people in their late 80s to people in their early 20s.

Michaela wants to compare a group of Professional Football Players with a group of High School Football Players

Annie wants to compare current U.S. Senators to current U.S Representatives.