A researcher wants to know whether gross motor coordination is better in the morning or in the afternoon. Using a within-subjects design, the researcher first tests 20 subjects on their ability to walk 6 feet on a balance beam early in the morning and then the same 20 subjects again in the afternoon. Upon finding no significant difference in performance between the morning and afternoon sessions, the researcher concludes that gross motor coordination is not influenced by time of day, at least as measured by the ability to walk on balance beams. The biggest problem with this conclusion is that: Group of answer choices Participants are likely to have varying experience with balance beams coming into the experiment There was only one level of the independent variable The independent variable was confounded by the order of the conditions