A study was conducted to see if herbal supplement helped to decrease 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. Throughout the same period, 42 subjects using placebo and high-fiber, low-calorie diet had the mean weight loss of 4.1 kg. And standard deviation of 3.9 kg.
Discuss why you fail to reject the null hypothesis if the confidence interval contains 0.