In each of the following situations, data are obtained by conducting a statistical study. Classify each statistical study as experimental or correlational. Statistics students collect data on the shower length and gender of the person taking the shower for a random sample of showers. The manager of a tuna canning factory is interested in finding out which set of machine settings results in a smaller variance of the fill weight of the tuna cans. She uses one set of machine settings for the day shift and a second set of settings for the night shift. The next day she uses the second set of settings for the day shift and the first set of settings for the night shift. Data are collected on the fill weights of the tuna cans. For a sample of college students using the ATM in the campus center, data are collected on the dollar amount withdrawn.