WeiWei is interested in determining whether Georgia Southern Armstrong students during COVID-19 are feeling more stress than college students in general. She asks people to fill out a brief 10-item rating scale about stress, where a higher rating indicates more stress. She then compares her data to a nationwide sample of college students who have filled out the same measure (mu = 7.6); the population standard deviation is 1.3. Both of these groups' data are positively skewed. What are the scale(s) of her variables? Question 10 options: a) There is only one variable, which is approximately interval in scale. b) The IV is nominal, and the DV is ordinal. c) The IV is nominal, and the DV is approximately interval. d) The IV is ordinal, and the DV is approximately interval