A civil engineer is interested in determining whether four different methods of estimating flood flow frequency produce equivalent estimates of peak discharge. When applied to the same watershed, each procedure is used six times on the watershed, and the resulting discharge data (in cubic feet per second) are recorded and displaced in the following table.

Method	Observations
1	0.34	0.12	1.23	0.70	1.75	0.12
2	0.91	2.94	2.14	2.36	2.86	4.55
3	6.31	8.37	9.75	6.09	9.82	7.24
4	17.15	11.82	10.95	17.20	14.35	16.82

(a) Perform ANOVA test under alpha = 0.05.

(b) Check the model by using residuals.

(c) Investigate the possible transformation to remove possible violations (nonhomogeneous and/or nonnormality).