For Joan's Doctoral Dissertation Experiment, 15 Wheelchair Users Were Assigned

For Joan's doctoral dissertation experiment, 15 wheelchair users were assigned to three groups with 5 in each group.These participants navigated in virtual-reality settings.Group 1 participants were in the virtual-reality setting a building) as wheelchair users.Group 2 participants were in the virtual-reality setting in a wheelchair pushed by a walking person.Group 3 participants walked without aid in the virtual-reality setting.Joan measured the number the time needed to complete the navigation of the virtual-reality setting.
a.What is the dependent variable?
b.What is the independent variables?
c.How many levels are there?
d.What is the N?