Guéguen and Jacob XXXXXXXXXXasked waitresses to wear different colored T-shirts on different days for a six-week period and recorded the tips left by male customers. The results show that male...

Guéguen and Jacob (2012) asked waitresses to wear different colored T-shirts on different days for a six-week period and recorded the tips left by male customers. The results show that male customers gave significantly bigger tips to waitresses when they were wearing red. For this study, identify the independent variable and the dependent variable.