he following results describe the effects of three fertilizer treatments on the dry biomass (mg) of above-ground shoots in 21-day-old rice plants inoculated with wild-typeRhizobium. The treatment labeled F10 is a control. NH4Cl and NH4NO3 are fertilizers.

> rice %>% group_by(fert) %% summarize (sd=sd(ShootDryMass ) ) # A tibble: 3 x 2 fert sd 1 F10 26.7 NH401 18.3 WN NH4NO3 23.1 Analysis of Variance Table Response: ShootDryMass of Sum Sq Mean Sq F value Pr ( >F) fert 2 20526 10263.0 19.485 2.585e-06 *# # Residuals 33 17382 526.7 Signif. codes: ( '* **' 0. 001 '* * ' 0. 01 '*' 0. 05 . ' 0.1 ' '1 Coefficients: Estimate Std. Error t value Pr(>|t/) (Intercept) 108.333 6. 625 16.352