To work out exercise 6.6 from Hobson’s book '' The weights (in grams) ofmac hine components ofa standard size made by four different workers on two different days are shown in Table; five components were chosen randomly from the output of each worker on each day. Perform an analysis of variance to test for differences among workers, among days, and possible interaction effects. What are your conclusions?

> folder <- "C:/Cauldron/garage/R/soulcraft/Volatility/Learn/Dobson-GLM/"
> file.input <- paste(folder, "Table 6.19 Machine components.csv",
+     sep = "")
> data <- read.csv(file.input, header = T, stringsAsFactors = F)
> data$day <- factor(data$day)
> data$worker <- factor(data$worker)
> summary(aov(data$weight ~ data$day + data$worker + data$day:data$worker))
                     Df Sum Sq Mean Sq F value    Pr(>F)
data$day              1  6.084   6.084  4.8435   0.03508 *
data$worker           3 54.622  18.207 14.4948 3.895e-06 ***
data$day:data$worker  3  2.958   0.986  0.7850   0.51117
Residuals            32 40.196   1.256
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

Between workers, the effect is significant

  1. No effect due to interaction