Courtney was on the track team and wanted to test the effects of her diet on her race times. she decided to test high carbohydrate meals and high protein meals for four weeks. she tested the effects by recording her 500 meter times one hour after each meal. for breakfast she had a high protein or high carbohydrate meal and for lunch, she would have the type of meal she did not select for breakfast. some days she had her high protein meal in the morning and and other days she had her high protein meal at lunch. she began recording her results and noticed that no matter what meal she had, her times were always faster at lunch. she did notice a trend of slightly faster times after her high carbohydrate meals when compared to her protein meals for the same time of day; however, she was unsure of the true impact. what is a factor in courtney's study that could result in misleading conclusions?