In 'Day at the Races', does each character have an equal chance of winning?

Short Version: No. Some racers have a better chance of winning.

  1. Boo (fastest)
  2. Whomp
  3. Bob-Omb
  4. Thwomp (slowest)

Long Version:

According to an analysis of 12,557 races by TAS Speedrunner KirkQ, the odds of each racer winning will very based on their starting animations.

To summarize, each racer can have one of three possible starting animations prior to choosing them. These are referred to as Fast, Normal, and Slow respectively.

Racer Starting Animations

Fast Boo: Flashing twice a second.
Normal Boo: Flashing once per two seconds.
Slow Boo: Not flashing, looking down.

Fast Whomp: Wobbling side to side.
Normal Whomp: Standing straight up.
Slow Whomp: Hunched over slightly.

Fast Bob-Omb: Bright fuse lit.
Normal Bob-Omb: Average fuse lit.
Slow Bob-Omb: No fuse lit.

Fast Thwomp: Rising and pounding quickly.
Normal Thwomp: Rising and pounding slowly.
Slow Thwomp: Sitting on the ground.

After 12,557 races, here were the first place odds for each racer based on animation.

First place odds

Fast Boo: 46.4%
Normal Boo: 35.9%
Fast Whomp: 33.5%
Fast Bob-Omb: 28.9%
Slow Boo: 27.3%
Normal Whomp: 25.9%
Slow Whomp: 24.6%
Normal Bob-Omb: 22.7%
Slow Bob-Omb: 19.8%
Slow Thwomp: 14.3%
Fast Thwomp: 13.0%
Normal Thwomp: 11.7%

In most scenarios, Boo was the fastest if he had Fast or Normal animations, while Thwomp was generally the worst pick regardless of his starting animation.