To test whether a new herbal drug is effective in preventing colds 100 people in the treatment group (with drug) 100 people in the control group (no drug) Outcome 1: 30 in the treatment group and 32 in the control group catch colds Outcome 2: 24 in the treatment group and 32 in the control group catch colds Can we conclude that the herbal formula is effective in preventing colds? Is the probability that the observed difference occurred by chance small, less than or equal to 1 in 20 (0.05)?