<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 onqunyiwe ifomula 18, ifomula 19 ingukuguquguquka okungahleliwe nefomula ephakathi 20 kanye nefomula yokwehluka 21. Umbuzo: Ingabe umusho 1 nomusho 2 usho into efanayo? Yebo noma Cha?  <response>: Yebo Yebo 