Question

I’m new to R. We have an assignment that i’m working on. The assignment is on creating R package to mimic Anova table. I have created all the necessary function that is mandated in the assignment. The function calculates the correct values, but I couldn’t make it display like ANOVA table that R’s built in anova() function can. This is my summary.oneway function

summary.oneway <- function(object, ...){

  #model <- oneway(object)
  fval <- object$FValue
  TAB <- list(t(object$AOV), "Mean Sq."= rbind(object$MSB, object$MSW),
              "F Value" = fval, p.value = object$p.value)

  res <- list(call=object$call, onewayAnova = TAB)
  class(res) <- "summary.oneway"
  res  
}

This is the output:

Analysis of Variance:
oneway.formula(formula = coag ~ diet, data = coagdata)

[[1]]
         Sum of Squares Deg. of Freedom
diet                228               3
Residual            112              20

$`Mean Sq.`
        1
[1,] 76.0
[2,]  5.6

$`F Value`
       1 
13.57143 

$p.value
           1 
4.658471e-05

Actual ANOVA output:

Analysis of Variance Table

Response: coag
          Df Sum Sq Mean Sq F value    Pr(>F)    
diet       3    228    76.0  13.571 4.658e-05 ***
Residuals 20    112     5.6                      
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

How can I achieve this format? Where and what am I missing?

Thank you so much for your help.

Kuni

Answer 1

The Anova output uses the print method print.anova you may want to take look at methods(print) and specifically stats:::print.anova

You will most likely want to create your own print function

 print.oneway <- function(object, ...) {
     foo
     bar
 }