Another approach to the data analysis is to use the eye, rather than the person, as the observational unit. For the 211 persons there were 422 measurements of refractive error: the accompanying table summarizes these measurements. The ANOVA of the 422 observations yields SS(between) = 258.97 and SS(within) = 5,143.9.

(a) Construct the ANOVA table and bracket the P-value for the F test. Compare with the P value obtained in Exercise 11.S.3. Which of the two P-values is of doubtful validity, and why?
(b) The mean refractive error for the sex-linked RP patients was -3.30. Calculate the standard error of this mean two ways: (i) regarding the person as the observational unit and using Spooled from the ANOVA of Exercise 11.S.3; (ii) regarding the eye as the observational unit and using Spooled from the ANOVA of this exercise. Which of these standard errors is of doubtful validity, and why?

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Mean Number of refractive Group Autosomal dominant RP Autosomal recessive RP Sex-linked RP Isolate RP Total cyes 54 40 36 292 422 crror +0.0 0.83 -3.30 0,84