<prompt> Umusho 1: Ukuze uthole umsebenzi olinganisekayo ongaguquki formula _ 18, formula _ 19 iyinombolo engahleliwe enesilinganiso formula _ 20 kanye ne-variance formula _ 21. Umusho wesibili: Kumsebenzi olinganisekayo ongaguquguquki ifomula 18, ifomula 19 iyinombolo ephakathi nendawo enefomula engahleliwe engu-20 kanye nefomula yokwehluka engu-21. Umbuzo: Ingabe umusho 1 nomusho 2 usho into efanayo? Yebo noma Cha?  <response>: Cha, akunjalo. 