Freitas, A., Figueiredo, T.S., Silva, N. and Miranda, M.C. 2018. Learning difficulties with median and quartiles concepts in the 8th grade students: formula versus plot comparative study. Indagatio Didactica. 10, 2 (Jul. 2018), 109-132. DOI:https://doi.org/10.34624/id.v10i2.11313.