Respuesta :
For the study conducted by the researchers,
- The type of study that was conducted is a matched-pairs design
- The appropriate t-interval for inference is a t-interval for a mean difference
How to determine the type of study?
From the question, we have the following highlights:
- One football was filled with air (the control group)
- The other was filled with helium (the experimental group)
When a study used a control group and an experimental group, then such study is a matched-pairs design.
How to determine the appropriate t-interval for inference?
The appropriate t-interval for inference for a matched-pairs design is the t-interval for a mean difference
Read more about matched-pairs design at:
https://brainly.com/question/16448112