Answer: 1. c. There are no differences in the mean completion times among the scents compared
2. Scent; Completion Time
Step-by-step explanation:
The Null Hypothesis of a research is that hypothesis which you aim to disprove because it holds that no significant relationship between the variables being researched exists.
In this scenario you are studying whether scent affects spatial reasoning abilities.
The Null Hypothesis will.be that which states that there is no relationship between scent and spartial reasoning therefore there will be no differences in the mean completion times among the scents compared.
The factor of interest is the variable that is being changed to examine a difference making it the SCENT in this scenario.
The dependent variable changes due to the Factor of Interest so it is the COMPLETION TIME.