Sometimes, the hot water produced by a solar water heater is not warm enough to meet the needs of the occupants of a building. A traditional water heater inside the building supplies additional thermal energy to the solar-warmed water. How can this method still reduce the overall amount of natural gas or electrical energy a building uses?

Dr. redbull conducts a study to determine whether her new energy drink children perform better on spelling tests. she randomly assigns children to one of two groups: group 1 receives her energy drink and group 2 receives water. she then gives both groups a spelling test and compares the results. which of the following is true about this study? a. group 1 is the dependent variable and group 2 is the independent variable. b. this is a correlational study. c. group 2 is the experimental group. d. the independent variable is the type of drink the children receive.