A study was conducted to see if an herbal supplement helped to reduce weight. After 12 weeks, 42 subjects using the herbal supplement and a high-fiber, low-calorie diet had a mean weight loss of 3.2 kg.
And a standard deviation of 3.3 kg. During the same period, 42 subjects using a placebo and a high-fiber, low-calorie diet had a mean weight loss of 4.1 kg. And a standard deviation of 3.9 kg.
At 0.05 , test the claim that the mean weight loss for the group using the herbal supplement is greater than the mean weight loss for the group using the placebo.