Consider these three variables: finishing times in a marathon, number of university dining hall meals eaten in a semester on a three-meal-a-day plan, and scores on a scale of extroversion. i) Which of these variables is most likely to have a normal distribution? Explain your answer.

ii) Which of these variables is most likely to have a positively skewed distribution? Explain your answer, stating the possible contribution of floor effect.

iii) Which of these variables is most likely to have a negatively skewed distribution? Explain your answer, stating the possible contribution of ceiling effect.