A researcher has developed a new drug designed to reduce blood pressure. In an experiment, 21 subjects were assigned randomly to the treatment group and received the new experimental drug. The other 23 subjects were assigned to the control group and received a standard, well-known treatment. After a suitable period of time, the reduction in blood pressure for each subject was recorded. A summary of these data is:

		n		s
	Treatment group (new drug):	21	23.48	8.01
	Control group (old drug):	23	18.52	7.15

Which of the following would lead us to believe that the t procedures were not safe to use here?

The sample medians and means for the two groups were slightly different.

The two population distributions are heavily skewed, and far from Normal.

Some subjects did not follow protocol, and these could be outliers in the data.

The two population distributions being studied are slightly non-Normal.