The HCIkey is a vector of factors representing correct
  answers of HCItest dataset.
data(HCIkey)A nominal vector with 20 values representing correct answers to items
  of HCItest dataset. For more details see HCItest.
McFarland, J. L., Price, R. M., Wenderoth, M. P., Martinkova, P., Cliff, W., Michael, J., ... & Wright, A. (2017). Development and validation of the homeostasis concept inventory. CBE-Life Sciences Education, 16(2), ar35. 10.1187/cbe.16-10-0305
HCItest for HCI multiple-choice dataset
HCI for HCI dichotomous dataset
HCIdata for HCI full dataset
HCIgrads  for HCI dataset of graduate students
HCIprepost for HCI pretest and posttest scores
HCItestretest for HCI test-retest dataset