Researchers Hypothesized That the New "Shake Weight" Would Yield a More

Researchers hypothesized that the new "Shake Weight" would yield a more effective workout than traditional barbell weight training. They found that using the "Shake Weight" for 6 minutes a day, three times a week, resulted in the greater improvement in strength than engaging in a 40-minute barbell regimen three times a week. They acknowledged, however, that they might have a Type I error. What does this mean?

A) The surprising effectiveness of the Shake Weight is probably due to chance or measurement error
B) The researchers thought the weight workouts were the same, when the Shake Weight was in reality more effective.