One way to reduce the use of water in agriculture is through drip irrigation ('irrigation goutte a goutte'), in which water is provided to plants via a tube. It is then very important to determine the effect of water on yield in order to justify the costs of irrigation. Dr. Therrien used different irrigation levels (controlled precisely) in different plots, and measured the resulting yield of tomatoes at the end of a season. Irrigation Yleld _ (Xi i)2 (Yi _ ?)2 (Xi _ XXYi _ Y) (Y1 _ ?i)2 water Xi Yi (mT-ha 1) (L'h'l) 0.9 14.3 0.36 0.25 0.30 0.006 1.1 14.0 0.16 0.64 0.32 0.171 1.4 15.2 0.01 0.16 -0.04 0.246 2 15 0.25 0.04 0.10 0.080 2.1 15.5 0.36 0.49 0.42 0.015 2:75 2:74 2:1.14 2:1.58 Z=1.10 Z=0.518 10) Dr. Therrien thinks that the simple linear regression should be statistically significant. Assist him in performing the test of significance with (I : 0.05