A behavioral scientist interested in the effect of exercise on the perceptions of well-being among older adults identified 30 residents of a retirement community and divided them into two groups of 15 residents. Both groups were encouraged to walk at least 20 minutes per day. One group, however, also participated in a structured exercise program that emphasized flexibility. After 6 weeks, the behavioral scientist mailed questionnaires to the 30 residents. Responses to an item asking residents to rate their perceptions of their health on a 10-point scale on which 1 indicated "very unhealthy" and 10 indicated "very healthy" are presented in the table that follows. Are the observed differences in health ratings of the two groups statistically significant at the .05 level of significance?
Walking and Flexibility: 5, 6, 6, 4, 9, 4, 7, 9, 6, 7, 9, 7, 4, 9, 8
Walking Only: 2, 3, 4, 3, 6, 7, 7, 6, 7, 4, 6