Improving adolescents habits. Most American adolescents dont eat well anddont exercise enough. Can middle schools increase physical activity among theirstudents? Can they persuade students to eat better? Investigators designed aphysical activity intervention to increase activity in physical education classesand during leisure periods throughout the school day. They also designed anutrition intervention that improved school lunches and offered ideas forhealthy home-packed lunches. Each participating school was randomly assignedto one of the interventions, both interventions, or no intervention. Theinvestigators observed physical activity and lunchtime consumption of fat.Identify the individuals, the factors, and the response variables in thisexperiment. Use a diagram like that in Figure 9.1 to display the treatments.
Chapter 13 ---- Comparing Two Means Comparing two means with the “Two Sample t-Test” (Two Independent Samples Design) Take two groups of people (items) randomly and take one measurement per person. These groups have not been matched up by any criterion but rather the people selected in group 1 are selected independently of the people in group 2. The people selected in group 1 do not influence in any way those selected in group 2. Example 1: Is a new teaching method more effective than the old method Select 20 people at random to be assigned to a class using the new method and select another 20 people at random to be in the old method group. The people in the two groups were not matched up by any criterion but rather simply taken from the same population at ra