Which of the following statements provides the best guidance for model building? if the value of r2 increases as more variables are added to the model, the variables should remain in the model, regardless of the magnitude of increase. if the value of the adjusted r2 increases as more variables are added to the model, the variables should remain in the model. if the value of r2 increases as more variables are added to the model, the variables should not remain in the model, regardless of the magnitude of the increase. if the value of the adjusted r2 increases as more variables are added to the model, the variables should not remain in the model.

Carla was trying to decide what to do saturday evening. she has $100 available to spend for the evening. she has narrowed her choices down to these events: braves game, a concert of an artist she likes, or the georgia aquarium. admission to the braves game is $25, hot dogs cost $10, sodas cost $5. the concert costs $25 for admission, $20 for a souvernir t-shirt, and $10 for a soda. the georgia aquarium has the show of a lifetime with an all you can eat and drink that costs $100. carla does not want to take any driving chances, so in addition to the cost of the aquarium, she will also need to pay for her uber/lyft, which is $15 each way. which option should carla choose if she wants to spend the least? based on that choice, what then is carla's oppotunity cost? fully explain your answer in at least one paragraph.